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<font face="tahoma" size="6"><strong>6. Animation</strong></font>
<img src="man_title_small.jpg" align="middle"><br><br>
<br>
<br>
<br>
This chapter explores the ways that Art of Illusion allows the creation
of animations. The tools available
are flexible enough to allow high quality 3D animations to be created
in an efficient way.<br>
<br>
Please note that the example animations are only simple examples of
what Art of Illusion is capable of
to demonstrate specific aspects. Also note that in order to keep the
file to a reasonable size, animations have had to be highly compressed
to gif images and thus their quality is far lower than that
actually achieved with Art of Illusion.
<br>
<br>
<a name="score"><strong><font color="#3300cc" size="5">6.1 The Score</font></strong></a><br>
<br>
Like many other 3D animation programs, Art of Illusion handles
animations through a score or timeline on
which various actions can be defined. Each object can have a range of
different tracks which run along
the score and which control various parameters such as position,
orientation, scaling as well as more
complex controls using skeletons. These will be looked at in detail in
the next few sections.<br>
<br>
<br>
<a name="score_layout"><strong><font color="#ff6633" size="4">6.1.1 The Score Layout</font></strong></a><br>
<br>
Let's look at the layout of the score in more detail:<br>
<br>
<table>
<tbody>
<tr>
<td><font face="tahoma" size="2">This
is what the score looks like. It can be viewed by selecting <b>Animation
-&gt; Show Score</b> from the
top menu bar, or by grabbing the drag bar at the very bottom of the window and
moving it up. The scale along the top shows the time in seconds. Down
the left hand side is a list of
currently selected objects together with their animation tracks, if
any. In this example, there is an
object called 'hand' which has position and rotation tracks. </font></td>
<td><img src="animation/anim_score.jpg"></td>
</tr>
</tbody>
</table>
The vertical green line shows the time position currently viewed in the
view windows. As this is dragged along, the objects in the scene are
updated to reflect their actual position in the animation sequence. The
position in the animation can also be controlled from the block of
commands in the
<b>Animation</b> menu:<br>
&nbsp;<img src="animation/anim_frame_control.jpg"><br>
<br>
The diamond symbols shown on the tracks indicate that a particular
position or orientation has been defined at this point in time. Such
positions are called 'keyframes' and details are given in the <a href="#keyframes">next
section</a>.<br>
<br>
Apart from the score itself, there are 5 other buttons on the right
hand side of the screen as shown below:<br>
<img src="animation/anim_score_icons.jpg"><br>
<br>
The top button gives the view we have just looked at. The next 2
buttons present the information in a different way; using curves
showing the change in the various parameters such as position, rotation
etc.
For the example above, clicking on the upper of the curve views and
selecting the 'position' track gives
the following display:<br>
<img src="animation/anim_score_curve.jpg"><br>
Here, the position of the object in the <font color="#0000ff">x</font>,
<font color="#008000">y</font> and <font color="#ff0000">z</font> axes is plotted against time.
For this particular example, x changes
from about 0.75 to -0.3 units as the time goes from 0 to 1 second.<br>
<br>
If more than one track is selected, then the curves are drawn on the
same set of axes in this mode. If
the second plot mode is selected with the <img src="animation/anim_mult_curve.jpg"> button, however, then
curves
from each track would be displayed on separate graphs. This is more
sensible if different types of track
are selected as the values are likely to be very different, e.g.
position values may be a few units as opposed to rotation values which
are likely to be at least tens of degrees.<br>
<br>
The bottom two buttons from this group are for switching between an
editing mode and a mode for altering
the vertical and horizontal scales on the score.<br>
<br>
The upper button <img src="animation/anim_edit_button.jpg">
is the editing mode which allows keyframes or curve points to be
selected and moved. Simply click on
any point to select it and drag to move it. Multiple points are
selected by pressing <shift> while
clicking on each point. The selected group can then be moved.<br>
<br>
The lower button <img src="animation/anim_scale_button.jpg">
allows the score axes to be scaled and moved. When selected, dragging
left and right with the mouse LMB moves the horizontal axes and
dragging up and down moves the vertical axes.
The axes are scaled by holding &lt;shift&gt; and dragging left
and right or up and down. These controls
can also be affected without clicking this button; holding the right
mouse button while dragging left/right
on the score allows the score to be moved and if &lt;shift&gt;
is held down as well, the score can be scaled.
The mouse wheel can also be used to move the score along left and right.<br>
<br>
<br>
<br>
<a name="keyframes"><strong><font color="#ff6633" size="4">6.1.2 Keyframes</font></strong></a><br>
<br>
Animation in Art of Illusion works by defining certain key actions,
e.g. moving an object to a certain
position, defining a particular skeleton pose etc., at specific points
in time. These points are called
keyframes. Having defined these, the program will calculate the
positions, poses etc. in between the keyframes
automatically by interpolation.<br>
<br>
Keyframes are generally set by moving the green time marker to the
appropriate time, changing the particular property of the object, e.g.
its position, orientation etc., and then selecting <b>Animation
-&gt; Keyframe Modified Tracks of Selected Objects</b>.
Alternatively, a keyframe can be produced at any time position for a
particular track by selecting the track(s) and clicking on <b>Animation
-&gt; Keyframe Selected Tracks</b>.<br>
<br>
Once a keyframe has been created, it can be selected by clicking on it
and edited through this block in the <b>Animation</b> menu:<br>
&nbsp;<img src="animation/keyframe_menu.jpg"><br>
<br>
<b>Edit Keyframe</b> allows various parameters relating to
the keyframe to be altered. The actual options
depend on the type of track so more details are given in the various
track sections later in this
chapter.<br>
<br>
<b>Delete Selected Keyframes</b> removes all currently
selected keyframes.<br>
<br>
<b>Bulk Edit Keyframes</b> allows the editing of a group of
keyframes as follows:<br>
<br>
</shift>
<table>
<tbody>
<tr>
<td><img src="animation/move_keyframes.jpg"></td>
<td><font face="tahoma" size="2"><b>Move..</b>
allows a block of keyframes to be moved to another point in time. The
dialogue on the left is displayed. The operation can be applied to <b>All
Tracks</b>, <b>All Tracks of Selected Objects</b> or
<b>All Selected Tracks</b>.<br>
<br>
You can then specify the time points between which you want keyframes
to be moved from and the time
you want to move them to. Note: any existing keyframes in the region
that is copied to, will be overwritten.<br>
<br>
<b>Copy ..</b> is similar to <b>Move ..</b>
but the original keyframes are retained as well as new ones
created at the copy to position. </font></td>
</tr>
</tbody>
</table>
<br>
<table>
<tbody>
<tr>
<td><img src="animation/anim_resize_keyframes.jpg"></td>
<td><font face="tahoma" size="2"> <b>Rescale..</b>
allows keyframes between a specified range to be rescaled in respect of
time. In this example,
the keyframes between 0.4 and 1.0 seconds are rescaled by a factor of
0.5 which compresses the keyframes
so that they happen in half the time.<br>
<img src="animation/anim_scale_ex.jpg"> </font></td>
</tr>
</tbody>
</table>
<br>
<table>
<tbody>
<tr>
<td><img src="animation/loop_keyframes.jpg"></td>
<td><font face="tahoma" size="2"> <b>Loop..</b>
allows keyframes between a specified range to be repeated a defined
number of times.
The dialogue allows entry of the range and the number of loops. The new
keyframes are then added to
the end of the range specified as in the example below:<br>
<img src="animation/loop_ex.jpg"> </font></td>
</tr>
</tbody>
</table>
<br>
<b>Delete..</b> simply deletes the range of keyframes that
you specify.<br>
<br>
<br>
</font><font face="tahoma" size="2">
Keyframes can be edited by double-clicking them on the score or by
selecting the keyframe from the Pose track and clicking on <b>Animation
-&gt; Edit Keyframe</b>. This will display a dialogue which
depends
on the object being controlled by the track.<br>
</font><br>
<font face="tahoma" size="2">
<br>
<a name="tracks"><strong><font color="#3300cc" size="5">6.2 Adding and Editing Tracks</font></strong></a><br>
<br>
This section looks in detail at the types of track that can be set up
for each object in the scene.
To add a new track to an object, select it and click on <b>Animation
-&gt; Add Track to Selected Objects</b>.
This enables a range of different tracks to be added:<br>
<img src="animation/tracks_menu.jpg">
<br>
The order of the tracks for each object is important as the effect of
each track on the object is calculated from the bottom up. Tracks can
be moved within the list by clicking and dragging in the
same way as objects can be moved in the <a href="layout.html#object%20list">Object List</a>.<br>
<br>
<a name="track weight">Each </a>object can have
several tracks of the same type. In this case, a <b>Weight</b>
can be defined for each track to define its relative influence. This
weight can itself vary with time by setting values
at specific keyframes. The <b>Weight</b> track is found by
clicking on the <img src="animation/right_arrow.jpg">
to the left on the appropriate track name in the list.<br>
<br>
Once created, tracks can be edited, deleted, duplicated and temporarily
enabled/disabled either by clicking the
right mouse button over the relevant track in the list on the score or
via the bottom section of the
animation menu.<br>
<br>
<a name="rigid_tracks"><strong><font color="#ff6633" size="4">6.2.1 Basic Rigid
Transformation Tracks</font></strong></a><br>
<br>
This refers to tracks that alter the object's position and orientation
without any geometric distortion of the
object, i.e. <b>Position</b> and <b>Rotation</b>
tracks.<br>
<br>
<b><font size="4">POSITION TRACKS</font></b><br>
<br>
To set up a basic Position Track, select the object and choose <b>Position
-&gt; XYZ (One Track)</b> from the <a href="#tracks">list
of tracks</a> in the
<b>Animation</b> Menu. At the most basic level, all you
need to do is to move the green time marker on the
score to the relevant point in time, move the object to the position
you want it in at that time and then
select <b>Animation -&gt; Keyframe Modified Tracks of
Selected Objects</b>. This will produce a diamond
keyframe at the required position on the score. Repeat this process for
other points in time as required.<br>
<br>
This is a simple example of a cube being translated in the z-axis with
only 2 keyframes defined as shown in the keyframe and plot views below
right resulting in the animation below:<br>
<br>
<img src="animation/anim_pos_ex.jpg"><img src="animation/box_position.gif" align="top"><br>
<br>
<a name="pos_track_op"><b><font color="#3393d2">POSITION
TRACK OPTIONS</font></b></a><br>
<br>
There are some options available for Position tracks. To bring up the
Track Options dialogue, either
double-click on the track name on the score or select the track and
click on <b>Animation -&gt; Edit Track</b>.
This will display a dialogue box similar to that below:<br>
<br>
<table>
<tbody>
<tr>
<td><img src="animation/position_track_opt.jpg"></td>
<td><font face="tahoma" size="2">At the
top is the <b><font color="#3393d2">Track Name</font></b>
which can be altered to anything you like.<br>
<br>
Next is the <b><font color="#3393d2">Smoothing
Method</font></b>. To understand this better, let's add
another keyframe to the above
animation. Move the time marker to 0.5 secs, select the position track
and click on <b>Animation -&gt;
Keyframe Selected Tracks</b>. Note that in this situation, <b>Keyframe
Modified Tracks of Existing
Objects </b>wouldn't have worked because the position of the box
at this point is no different than it was before. Having created the
keyframe, we can go to the plot view in edit mode and move the new
point
as shown below:<br>
<table>
<tbody>
<tr>
<td><img src="animation/anim_pos_smooth_ex1.jpg"></td>
<td><font face="tahoma" size="2">As
can be seen, the curve through the points is smooth and passes through
all the points. That is
because the default smoothing method is 'interpolating'. The other
choices for the <b>Smoothing Method</b>
are: <img src="animation/track_smoothing_options.jpg"> </font></td>
</tr>
</tbody>
</table>
</font></td>
</tr>
</tbody>
</table>
<br>
The other <b><font color="#3393d2">Smoothing Methods</font></b>
produce the following curves:<br>
<table>
<tbody>
<tr>
<td><img src="animation/anim_smooth_methods.jpg"></td>
<td><font face="tahoma" size="2">In
terms of the effect on the animation, <b>Interpolating</b>
and <b>Approximating</b> produce a gradual deceleration of
the box. With <b>Approximating</b> method, both velocity
and acceleration
are continuous whereas the acceleration changes discontinuously with <b>Interpolating</b>.
This
results in a smoother animation for the <b>Approximating</b>
method.<br>
<br>
<b>Discontinuous</b> produces a sudden change in
position.<br>
<br>
<b>Linear</b> produces a box moving at constant speed
up to the second keyframe, then a slower constant speed to the final
position.<br>
<br>
All have their uses in different situations. </font></td>
</tr>
</tbody>
</table>
<br>
<b><font color="#3393d2">Track Mode</font></b>
is either <b>Absolute</b> or <b>Relative</b>.
Absolute means that the object position is calculated as displacements
from the origin (0,0,0). Relative mode is where the values are
displacementsfrom the result of the tracks beneath it in the list.<br>
<br>
<table>
<tbody>
<tr>
<td><font face="tahoma" size="2">For
example, we can add a Position track to the animation above and select <b>Relative</b>
Mode for it. We need to make sure it sits above the Absolute position
track because transformations get applied from the bottom up.<br>
<br>
We could then use the Relative track to add displacements to the main
motion
of the cube, e.g. make it shake as it moves. In this example, the
Relative track was keyframed every 0.2 secs using <b>Animation
-&gt; Keyframe Selected Tracks </b>. The x and y coordinates
of the resulting keyframes were then moved to 'random' positions in the
plot view. The effect is that
the Absolute position on the cube is initially determined from the
Absolute track; then the Relative
track displaces the x and y positions by the coordinates specified.<br>
</font></td>
<td><img src="animation/anim_pos_rel.jpg"></td>
</tr>
</tbody>
</table>
<br>
<br>
<a name="apply"><b><font color="#3393d2">Apply
To</font></b></a> determines which part of the object
is controlled by the track and is either the <b>Object Origin</b>
or one of the joints in the <a href="object_types.html#skeletons">skeleton</a>.
<br>
For instance, in this example of a pendulum, a single bone joint has
been placed at the pivot position and
used as the part of the object to which the position track applies. The
rotation track is applied to the object's centre and the position track
then acts to reposition the object so that the 'pivot' is fixed
at the keyframed position:
<table>
<tbody>
<tr>
<td><img src="animation/pivot.jpg"></td>
<td><img src="animation/pendulum.gif"></td>
</tr>
</tbody>
</table>
<br>
<br>
<br>
<b><font color="#3393d2">Coordinate System</font></b>
is the set of axes under which the transformations
are applied, i.e. where the origin is and how the axes are oriented.
There are either 3 or 4 possible options for this, depending on which
Track Mode is set:<br>
<img src="animation/coord_system_opts.jpg">
<br>
The <b>World</b> coordinate system is the main coordinate
system that Art of Illusion works in.<br>
<br>
The <b>Parent</b> option is for objects that are
'children' of other objects. In most cases, you will
want the children to move, rotate etc. with their parent objects. In
this case, give the children objects
position tracks and set the <b><font color="#3393d2">Coordinate
System</font></b> to <b>Parent</b>. Keyframe
at least one time position, e.g. at time 0, to set up this relationship
and the children objects will then
follow their parents.<br>
<br>
<b>Other Object..</b> is similar to the <b>Parent</b>
option except that any object can be made to follow
any other object. Selecting this option, makes the <img src="animation/anim_coord_set.jpg"> button become
available. Pressing this allows the selection of the object, or of any
bone of any object with a
defined skeleton, to be followed.<br>
<br>
<b>Local</b> is only available for <b>Relative</b>
mode tracks and allows transformations to be made
relative to the object's own co-ordinate system which is defined via
the object layout.<br>
<br>
<br>
<b><font color="#3393d2">Track Affects</font></b>
allows the ability to restrict the motion to certain
axes only.<br>
<br>
<br>
<a name="pos_key_edit"><b><font color="#3393d2">EDITING
POSITION KEYFRAMES</font></b></a><br>
<br>
Keyframes can be edited by double-clicking them on the score or by
selecting a keyframe from the Position track and clicking on <b>Animation
-&gt; Edit Keyframe</b>. This
displays the following dialogue:<br>
<table>
<tbody>
<tr>
<td><img src="animation/pos_edit_key.jpg"></td>
<td><font face="tahoma" size="2">The
first 3 entries allow the alteration of the objects position in each of
the 3 axes in the defined
coordinate system. This is a way of more accurately specifying
positions as opposed to editing on the
plot view.<br>
<br>
The next entry is for <b><font color="#3393d2">Time</font></b>
allowing you to specify explicitly the time position of the keyframe.<br>
<br>
The lower half of the dialogue allows further refinement of the <b><font color="#3393d2">Smoothing Method</font></b>. For
<b>Interpolating</b> and <b>Approximating</b>
smoothing methods, the curve can be given a <b><font color="#3393d2">Smoothness</font></b> value
which determines how smooth the curve is. In addition, the part of the
curve to the left of the keyframe (i.e. the time period before the
keyframe)
can be set to a different <b><font color="#3393d2">Smoothness</font></b>
than the curve to the right of the keyframe (i.e. the time period after
the keyframe). </font></td>
</tr>
</tbody>
</table>
<br>
<br>
It is also possible to set up separate position tracks to allow
independent control
of movements in the X, Y and Z directions. This can be done
automatically by selecting
<b>Animation -&gt; Add Track to Selected Objects -&gt;
Position -&gt; XYZ (3 Tracks)</b>. In this instance
3 tracks are produced each with <b>Track Affects</b> set
to one of X, Y or Z.<br>
<br>
<b><font size="4">ROTATION TRACKS</font></b><br>
<br>
Basic rotation tracks are again created by selecting <b>Animation
-&gt; Add Track to Selected Objects -&gt; Rotation -&gt;
XYZ (One Track)</b>. The basic method of setting up a track is
similar to Position Tracks; move to the appropriate time, rotate
the object to the orientation (in degrees) required at that time, and
keyframe it. Below is a simple example
with a cube rotating in the x and z axes set up with 2 keyframes:<br>
<img src="animation/anim_rot_ex.jpg"><img src="animation/box_rot.gif" align="top"><br>
<br>
<b><font color="#3393d2">ROTATION TRACK OPTIONS</font></b><br>
<br>
The options dialogue for Rotations is displayed by double-clicking the
track name and looks as follows:<br>
<table>
<tbody>
<tr>
<td><img src="animation/rot_track_opt.jpg"></td>
<td><font face="tahoma" size="2">Most
of the settings are identical to the Position Track options. See <a href="#pos_track_op">
this section</a> for details.<br>
<br>
Note that with Rotations, a child object or an object set to another
object's coordinate system will
need to have both Position and Rotation tracks in place and set to the
appropriate coordinate setting in order to work properly.<br>
<br>
The only difference, in fact is the <b><font color="#3393d2">Isotropic
(Quaternion) Rotations</font></b>
option. Switching this on means that the end point of the rotation is
more important that the process
of rotations involved in getting there. The program does not
necessarily follow the specified rotation
values in each axes but gets to the endpoint by the shortest path
possible. For example, if you set a rotation of 270 degrees in the
z-axis, Art of Illusion actually treats this as -90 degrees if
quaternion rotations are turned on. Therefore, if you need to set a
rotation greater than 180 degrees in any axes, you need to switch this
option off. Bear in mind, however, that if you do this, that the x, y,
and z rotations are then performed independently in this order: z, x, y
and the animation might not do what you expect. In this situation it is
best to rotate only one axis at a time and use parent-child coordinate
systems to carry out more complicated rotations. </font></td>
</tr>
</tbody>
</table>
<br>
<br>
<a name="rot_key_edit"><b><font color="#3393d2">EDITING
ROTATION KEYFRAMES</font></b></a><br>
<br>
Keyframes can be edited by double-clicking them on the score or by
selecting a keyframe from the Position track and clicking on <b>Animation
-&gt; Edit Keyframe</b>. This
displays the following dialogue:<br>
<table>
<tbody>
<tr>
<td><img src="animation/edit_rot_keyframe.jpg"></td>
<td><font face="tahoma" size="2">The
first 3 entries allow the alteration of the objects orientation in each
of the 3 axes in the defined
coordinate system at the point in time of the keyframe.<br>
<br>
As with the keyframes in the Position Tracks, the smoothness of the
orientation vs time curves before
and after the keyframe can be set. </font></td>
</tr>
</tbody>
</table>
<br>
<br>
As with Position tracks, there is a way of automatically setting up
certain types of track through the
<b>Animation -&gt; Add Track to Selected Objects -&gt;
Rotation</b> menu. From here, you can choose to have
separate tracks for X, Y and Z and Quaternion rotations tracks set up
automatically.<br>
<br>
<b><font size="4">SET PATH FROM CURVE</font></b><br>
<br>
This is a special method of setting Position and Rotation Tracks for an
object using an existing curve
created with either of the <a href="object_types.html#curves">curve
drawing tools</a>.<br>
<br>
To perform this, select the object and the curve from the Object List
and click on <b>Animation -&gt;
Set Curve from Path </b>. This will display a dialogue similar
to that below:<br>
<table>
<tbody>
<tr>
<td><img src="animation/set_path.jpg"></td>
<td><font face="tahoma" size="2">Here
you can select the object and curve (if more than one were selected
initially) to use.<br>
<br>
You can also specify whether the orientation of the object should
follow the curve or remain fixed. In
the latter case, no Rotation Track will be produced.<br>
<br>
There are 3 options for <b>Keyframe Spacing</b>: <b>Uniform
Spacing</b>, <b>Uniform Speed</b> or <b>Uniform
Acceleration</b>. Depending on which you set, there are then
additional parameters that can be specified:<br>
<br>
<b>Start Time</b> and <b>End Time</b>
define how quickly the object moves along the curve. If <b>Uniform
Speed</b> or <b>Uniform Acceleration</b> is
selected, then these values will depend on speed and/or acceleration
which can be specified in the remaining dialogue boxes. </font></td>
</tr>
</tbody>
</table>
<br>
<br>
The example below is a simple example. The curve was drawn as the path
followed by a bouncing ball. The
path of the sphere was then set to that of the curve with constant
speed (not physically realistic, or course).
The result is the automatically created Position Track and the
animation shown.<br>
<table>
<tbody>
<tr>
<td><img src="animation/set_path_setup.jpg"></td>
<td><img src="animation/ball.gif"> </td>
</tr>
</tbody>
</table>
<br>
<br>
<br>
<a name="proc_tracks"><strong><font color="#ff6633" size="4">6.2.2 Procedural Rigid
Transformation Tracks</font></strong></a><br>
<br>
Procedural animation tracks allow the position and orientation of any
object to be controlled explicitly
using mathematical equations. This is useful, for instance, in the
simulation of real-life physics.<br>
<br>
To add a procedural animation track, select the object and click on <b>Animation
-&gt; Add Track to Selected
Objects</b> and choose either <b>Position -&gt;
Procedural</b> or <b>Rotation -&gt; Procedural</b>.
Double-click
the track name on the score or select it and click on <b>Animation
-&gt; Edit Track </b>. This will display
the procedure editor which is virtually identical to that used for
procedural textures/materials. The obvious difference is that the
output modules are X, Y and Z. In the case of a positional track, these
are
the x,y and z positions and, in the case of a rotation track, these
will be the orientation around each axis.<br>
<br>
The <b>Insert</b> menu allows various value and function
modules to be added to the procedure. See
<a href="textures.html#proc_tex">Procedural Textures</a>
for more details of the available modules.<br>
<br>
The <b>Properties</b> menu item allows the definition of
the type of smoothing and the coordinate system as
with the <a href="#pos_track_op">simple position track</a>.
<table>
<tbody>
<tr>
<td><font face="tahoma" size="2">Consider
the example of a ball being thrown into the air upwards (y-axis) and
along the x-axis. The physical equations describing this projectile
motion tell us that the distance in the x-direction is given by <b>x
= u t cos <font face="symbol">a</font></b>
where <i>u</i> is the velocity (which we'll assume for the
moment is constant) <i>t</i> is the time
and <font face="symbol"><i>a</i></font>
is the angle from the horizontal as shown on the figure on the right:<br>
<br>
The distance along the y-axis is given by <b> y = h + u t sin <font face="symbol">a</font> - 0.5 g t<sup>2</sup></b>
where <i>h</i> is the initial height and <i>g</i>
is the acceleration due to gravity (= 9.81 m/s<sup>2</sup>)
</font></td>
<td><img src="animation/projectile_diagram.gif"></td>
</tr>
</tbody>
</table>
<br>
We're controlling the <i>position</i> of the ball so we
need to put these equations into a procedural position track. One
possibility, shown below, is to use the <b>Expression</b>
module and feed the outputs into
the relevant X and Y output modules. In this example, the velocity
of projection is set through a parameter so that different projections
could be set up easily. This could
also be done with the other variables, such as initial height (which is
1.0 in this example) and angle of projection which was set at 0.79
radians (45 degrees) in this example.<br>
<br>
<img src="animation/project_proc.jpg"><img src="animation/projectile.gif"><br>
In procedural animation tracks, it is also possible to keyframe any
parameters that form part of the procedure. For example, if we amend
the procedure above to add a wind effect as follows:<br>
<table>
<tbody>
<tr>
<td><img src="animation/project_proc2.jpg"></td>
<td><font face="tahoma" size="2">Here,
I have introduced the new parameter <i>wind effect</i>
which is Input2 to the expression controlling
the x displacement. The expression has been slightly modified to add a
subtraction of the wind effect
from the x position. This is a very simplistic simulation that will
enable us to specify how far the
wind is pushing back the ball.<br>
<br>
Now, we can keyframe this parameter by moving the time marker to a
certain time point and selecting <b>Animation -&gt; Keyframe
Selected Tracks </b>. This produces a keyframe at the current
time
position on the score. Double-clicking the keyframe displays a dialogue
box that allows the value
of the keyframe to be specified as shown below: </font></td>
</tr>
</tbody>
</table>
<br>
<table>
<tbody>
<tr>
<td><img src="animation/proc_param_key.jpg"></td>
<td><font face="tahoma" size="2">Here,
the value of the parameter can be set for the particular point in time.
The value of the parameter
at any point in time will then be interpolated between keyframed values
using the type of smoothing
selected from the Properties menu option in the procedure editor.<br>
<br>
As before, the smoothing value can be specified if the smoothing method
is interpolating or approximating and the left and right smoothness can
be separately defined.<br>
<br>
Specifying the value at a number of time positions produces the
simplistic wind effect shown on the right.
Clearly, more sophisticated and realistic simulations could be
produced. </font></td>
<td><img src="animation/projectile_wind.gif"></td>
</tr>
</tbody>
</table>
<br>
<br>
Note that procedural animation tracks can also be used to apply motions
on top of previous motions.
Whenever x, y or z values are used within the procedure editor, they
are the positions or orientations
of the object just before this track is applied. So, for example, the
following procedure would double
any movements made by previous tracks in the x axis:<br>
<img src="animation/proc_scale.jpg"><br>
<br>
<br>
<a name="pose_tracks"><strong><font color="#ff6633" size="4">6.2.3 Pose Tracks and
Skeletons</font></strong></a><br>
<br>
Pose tracks are a way of keyframing other object properties and have a
particular use for mesh objects.<br>
<br>
<b><font color="#0000ff">Pose Tracks for Primitive
Geometric Objects</font></b><br>
For Primitive geometric objects, the properties that can be edited are
those that can be set using the <a href="editing_objects.html#edit%20object">Edit Object</a>
(i.e. scaling parameters). To apply, add
a Pose Track via <b>Animation -&gt; Add Track to Selected
Objects -&gt; Pose</b>. Now, add a keyframe at the time
at which you want to set the scaling parameters by selecting the pose
track and choosing <b>Animation -&gt; Keyframe Selected
Tracks</b>.
Double-click the keyframe to bring up the Edit Object dialogue, set the
scaling parameters and click OK. Repeat for other times as required.
The values of these parameters can also be set directly at the current
scene time via the <a href="layout.html#object_list">Object
Properties Panel</a>. &nbsp;The smoothness of the
interframe interpolation can be set via the <a href="#pose_track_dial">track dialogue</a>.<br>
<br>
<b><font color="#0000ff">Pose Tracks for Lights</font></b><br>
Pose tracks can also be set for lights to control <b>Colour</b>
and <b>Intensity</b> (all light types), <b>Radius</b>
and <b>Decay Rate</b>(for Point and Spot lights) and <b>Cone
Angle</b> and <b>Falloff Rate</b> (for Spotlights).
This works in a similar way to primitive geometric objects; add
a Pose Track, keyframe at required time and Edit Keyframe to fix the
light parameters at that time
point. &nbsp;</font><font face="tahoma" size="2">The
values of these parameters can also be set directly at the current
scene time via the <a href="layout.html#object_list">Object
Properties Panel</a>.</font><br>
<font face="tahoma" size="2">
<br>
<b><font color="#0000ff"><a name="camera_filter_anim">Pose Tracks for Cameras</a></font></b><br>
<a href="rendering.html#camera_options">Camera properties</a>
<b>Focal Length</b>, <b>Depth of Field</b>
and <b>Field of View</b> can also be animated via pose
tracks. Again this works as with primitives and
lights; add a Pose Track, keyframe at required time and Edit Keyframe
to fix the camera parameters at that time point. &nbsp;</font><font face="tahoma" size="2">The values of these parameters
can also be set directly at the current scene time via the <a href="layout.html#object_list">Object Properties Panel</a>.</font><br>
<font face="tahoma" size="2">
<br>
<a href="rendering.html#camera_filters">Camera Filter</a>
parameters can also be animated with time using Pose Tracks. The method
is slightly different; first add the required filters to the camera
(see <a href="rendering.html#camera_filters">Camera
Filters</a> for details), then add a pose track.
Expanding the Pose Track on the score by clicking the small arrow to
the left of it displays a list of
tracks corresponding to each filter. Keyframes can then be added to the
relevant tracks by highlighting them and selecting <b>Animation
-&gt; Keyframe Selected Tracks</b>. An example is shown below:<br>
<br>
<img src="animation/flash.jpg"><img src="animation/lightning_flash.gif"><br>
<br>
<br>
<b><font color="#0000ff">Pose Tracks for Mesh
Objects, Tubes and Curves</font></b><br>
With mesh objects, tubes and curves, Pose tracks work in a similar way
to Position tracks but at the vertex level.
The basic premise is that you work with an object that must have a
fixed number of vertices. You then set up various 'poses' of the object
by manipulating the object in its editor. Art of Illusion then looks
at the position of each vertex in the object and how it changes between
poses. The path that each vertex
takes is then calculated by interpolating for the frames in between the
keyframed poses.<br>
<br>
Mesh objects with skeletons work slightly differently in that the
position of the bones of the skeleton
are calculated for each intermediate frame, then the vertex positions
of the mesh are calculated based
on the bone positions.<br>
<br>
To add a Pose Track to an object select <b>Animation -&gt;
Add Track to Selected Objects</b> and choose
<b>Pose</b>. As with rigid transformation tracks, setting
up an animation is based on moving the time
marker to the appropriate point in time on the score, editing the
particular object property using the
appropriate dialogue and keyframing the modified tracks. Alternatively,
a keyframe can be placed at the
required time using <b>Animation -&gt; Keyframe Selected
Tracks</b> which can then be edited through
<b>Animation -&gt; Edit Keyframe </b>.<br>
<br>
For a mesh object, when you add a Pose Track the following warning is
displayed:<br>
<img src="animation/pose_warning.jpg"><br>
To create a Pose for a mesh actor, move the time marker to the required
time on the score and double-click
the object in the Object List. This displays a dialogue similar to that
below:<br>
<table>
<tbody>
<tr>
<td><img src="animation/pose_ex1.jpg"></td>
<td><font face="tahoma" size="2">On the
left hand side is a list of defined 'gestures' which are particular
instances of the mesh. At first there is only one: Default Pose which
is
the object in the position in which it was created. This gesture cannot
be deleted. To create a new gesture, select this default pose and click
on <span style="font-weight: bold;">Duplicate</span>.
Enter a name when prompted and this will add a new gesture to the list
and open up the object editor to allow the object to be edited in much
the same way as<span style="text-decoration: underline;"> </span><a style="text-decoration: underline;" href="object_types.html#triangle%20meshes">normal</a>
except that you will not be able delete any vertices or add any new
ones by extruding or subdividing.<br>
<br>
Once the mesh has been edited, click on OK to update the new gesture.
To assign a gesture from this
list to the current time, select it and click on <img src="animation/pose_add.jpg">. This adds the gesture to the <b>Current
Pose</b> list. This list defines how the mesh looks at that
moment in time: The final pose is the weighted sum of all the gestures
in this list, treating these gestures as <i>displacements</i>
from the
default pose. You can set the <b>Weight</b> by selecting
the gesture in the Pose list and typing a <b>Weight</b>
value in the box beneath the list. Or you can simply add a single
gesture to the list and click OK. If you look at this dialogue at a
point in time
between 2 keyframes, you will see that the <b>Weight</b>
of each gesture will have been calculated accordingly. It is also
possible to set negative <b>Weight</b> values.<br>
<br>
There are 2 other options available from this dialogue; <b>Save</b>
allows you to create a new gesture
which is equal to the current weighted average of the gestures in the <b>Current
Pose</b> list.<br>
</font></td>
</tr>
</tbody>
</table>
<br>
<b>Extract</b> saves the current pose determined from the
defined set of gestures in the <b>Current Pose</b> list as
a new mesh object.<br>
<br>
Once you have left the mesh Pose dialogue, set the keyframe for this
new pose by selecting <b> Animation
-&gt; Keyframe Modified Tracks of Selected Objects </b>.<br>
<br>
Using Pose Tracks for mesh objects allows effects such as morphing:<img src="animation/thingmorph.gif"><br>
<br>
<br>
<br>
Note that the <a href="layout.html#object_list">Object
Properties Panel</a>
can also be used for more direct keyframing of Pose Tracks for Actors.
&nbsp;When you click on the Actor, the Properties Panel will show a
list of the gestures that have been added to the Current Pose list.
&nbsp;The weights of each can then be set in the Properties Panel
either by directly entering numbers or by using the knobs.
&nbsp;The
weights can then be keyframed via </font><font face="tahoma" size="2"><b> Animation
-&gt; Keyframe Modified Tracks of Selected Objects </b>or
CTRL-SHIFT-K.</font><br>
<font face="tahoma" size="2"><br>
<br>
<br>
Using skeletons in animation is often an efficient way of creating new
gestures and poses. To do this, create a skeleton and bind it to the
mesh. Then, in the same way described above for each gesture, simply
move the bones as required and keyframe the pose. Below is an example
using 3 gestures, in addition to the default, and 5 keyframes; the
default was used at the beginning and the end:<br>
<table>
<tbody>
<tr>
<td><img src="animation/pose_ex_score.jpg"></td>
<td><img src="animation/pose_anim_ex.gif"><br>
</td>
</tr>
</tbody>
</table>
<br>
<br>
The <a name="pose_track_dial">options dialogue </a>for
the Pose Track is displayed by double-clicking the track name on the
score:<br>
<table>
<tbody>
<tr>
<td><img src="animation/pose_track_opts.jpg"></td>
<td><font face="tahoma" size="2">The
options are fewer than for the rigid transformation tracks.<br>
<br>
The <b>Track Name</b> can be changed to any name of choice.<br>
<br>
The <b>Smoothing Method</b> refers to the way the
parameter is interpolated between frames. In the case
of mesh objects, the relevant parameter is the <b>Weight</b>
of the various gestures making up the pose.
See <a href="#pos_track_op">above</a> for details
on the different smoothing methods.<br>
</font></td>
</tr>
</tbody>
</table>
<br>
The <b>Track Mode</b> can be either <b>Absolute</b>
or <b>Relative</b>. <b>Absolute</b> tracks
effectively
overwrite any other Pose tracks further down the list whereas <b>Relative</b>
tracks add to previous Pose
tracks.<br>
<br>
<a name="rel_pose_tracks"><b>Relative</b> pose
tracks </a> are useful for building up complex poses whilst
retaining better control of
different motions. In the example below, I have set up a series of
poses for a simple arm model. There are
seperate poses for each of the digits in a closed position and another
pose for the wrist. By creating 2
Pose tracks; one for the fingers (Absolute track mode) and one for the
wrist (Relative track mode), adding/modifying the wrist movement only
is much easier than having to separately edit each keyframe in a
combined Pose track .<br>
<img src="animation/pose_rel_poses_dials.jpg"><br>
<br>
For example, adding/removing the wrist movement is as easy as
enabling/disabling the wrist track:<br>
<br>
<img src="animation/hand_no_wrist.gif"><img src="animation/hand_rel_pose.gif"><br>
<br>
<br>
<br>
<br>
<b><font color="#0000ff">Child Objects and Animating
Poses</font></b><br>
<br>
Suppose we added some eyes (as child objects) to the snake in the
previous example. As the snake's head moves around we would like the
eyes to move with the head. Try this for yourself and see the results.
Child objects move and rotate with their parent object by default, but
in this case the eyes don't move. Why? Because the snake's position and
rotation doesn't actually change in the example above. The pose track
changes and it is only the snake's posture that moves to reflect this.<br>
<br>
Child objects move and rotate with their parent object by default. This
means that the coordinate system used for the child objects (eyes) is
set to 'Parent' by default. In the snake example, we'd like the eyes to
move with the pose of the snake as well. We can achieve this by setting
the coordinate system
of the eye objects to be linked to a bone within the parent mesh.<br>
<br>
To make the eyes follow the pose, double-click the position track for
the eyes from the score (or click
right and select <b>Edit Track</b>)and set the <b>Coordinate
System</b> to <b>Other object...</b>.
Now the <img src="animation/anim_coord_set.jpg"> button
becomes available. Pressing this allows the selection of any object, or
of any bone of any object with a defined skeleton, to be followed. If
you select the snake object and expand the list of sub-items for the
object you will see a list of bones that the snake object uses. Pick a
bone close to the position of the eyes and the eyes will now move with
the pose. Repeat/copy these steps with the rotation tracks as well.<br>
<br>
There are several points to note:<br>
<br>
You can still set keyframes for the child objects and animate them in
their own right. The position and rotation tracks will combine with the
other movements imposed by the parent object.<br>
<br>
You will need to set at least one keyframe for each child object to
establish the coordinate system
relationship.<br>
<br>
The objects following other object's coordinate systems in this way do
not necessarily have to be children of that object but in most cases it
makes sense if they are.<br>
<br>
<a name="bind">To make life easier, child objects can be
bound automatically to their parent's skeleton.</a> Simply select
the children of the parent (individually or by selecting parent and
choosing <b>Edit -&gt; Select Children</b>) and click <b>Animation
-&gt; Bind to Parent Skeleton</b>. This tool binds each
object
to the nearest bone in the parent's skeleton, creates Position and
Rotation tracks for each child, and
keyframes them to set up the relationship.<br>
<br>
<br>
<a name="distort_tracks"><strong><font color="#ff6633" size="4">6.2.4 Distortion Tracks </font></strong></a><br>
<br>
Distortion tracks are used to modify the surface of any geometrical
object in a procedural way. There
are 7 distortion tracks currently available in Art of Illusion: <a href="animation.html#bend">Bend</a>, <a href="animation.html#custom">Custom</a>, <a href="animation.html#scale">Scale</a>, <a href="animation.html#shatter">Shatter</a>, <a href="animation.html#twist">Twist</a>, <a href="animation.html#IK_track">Inverse Kinematics</a>
and <a href="animation.html#skel_shape">Skeleton Shape</a>.
The first 5 act directly on the object's surface and can be used for
any geometrical objects. The latter 2 are applied to the skeletons of
meshes and consequently indirectly
alter the mesh's surface. Each track is discussed separately in detail
below:<br>
<br>
Note that for the first 5 distortion tracks, if the object in question
is a mesh, the distortion is applied to each vertex of the
control mesh <i>before</i> the surface is subdivided. That
makes it fast, and keeps the surface smooth.
If the object is not a mesh, it is first converted to a triangle mesh
with the surface accuracy specified for rendering. The transformation
is then applied to each vertex of that mesh. Bear in mind
that this might not give the results you expect. For example, suppose
you use a Scale track to enlarge a Sphere, and render it with surface
accuracy 0.01. The sphere is first triangulated with
accuracy 0.01, then the resulting mesh is enlarged - which means it now
has errors greater than 0.01.
<br>
One general tip for distortion tracks is to ensure there are a
reasonable number of vertices in the model.
That way the distortions are smoother and more predictable.<br>
<br>
<a name="bend"><b><font color="#3393d2">BEND
TRACK</font></b></a><br>
<br>
As the name suggests, this track bends the object through an angle
about a specified axis and in a specified direction.<br>
<br>
To add a Bend Track to an object, select the object and choose <b>Animation
-&gt; Add Track to Selected
Objects -&gt; Distortion -&gt; Bend</b>. The properties
of the track can be edited by double-clicking the track
name on the score or clicking right and selecting <b>Edit Track</b>.
This displays the Bend Track dialogue window like that below:<br>
<br>
<table>
<tbody>
<tr>
<td><img src="animation/bend_track_dial.jpg"></td>
<td><font face="tahoma" size="2">The <b>Track
Name</b> can be changed to anything you like and will appear in
the track list on the score.<br>
<br>
The <b>Smoothing Method</b> defined the way that bend
angles are interpolated between keyframed values.
The options are detailed <a href="#pos_track_op">above</a>.<br>
<br>
The <b>Bend Axis</b> is the axis away from which the
object bends.<br>
<br>
The <b>Bend Direction</b> determines in which direction
the object bends away from the axis specified
by the Bend Axis.<br>
<br>
<b>Reverse Bend Direction</b> alters the way in which
the object bends, with the opposite end being
fixed and the other end undergoing the bend.<br>
<br>
The <b>Coordinate System</b> determines whether the bend
axis and direction are defined from the object's
coordinate system or from the scene origin and orientation. </font></td>
</tr>
</tbody>
</table>
<br>
To define the <b>Bend Angle</b> values, add keyframes at
the required times by moving the time marker
to that time and selecting <b>Keyframe Selected Tracks</b>.
The keyframes can then be edited by
double-clicking them on the score to display the dialogue window below:<br>
<br>
<table>
<tbody>
<tr>
<td><img src="animation/bend_key_dial.jpg"></td>
<td><font face="tahoma" size="2">Here
you can set the required <b>Bend Angle</b> in degrees and
the <b>Time</b>.<br>
<br>
If either <b>Interpolating</b> or <b>Approximating</b>
smoothing was specified in the track options
dialogue then the <b>Smoothness</b> value can be specified.<br>
<br>
The <b>Smoothness</b> of the curve before the specified
time can also be made different to that after the time by ticking the <b>Separate
Left and Right Smoothness</b> box. </font></td>
</tr>
</tbody>
</table>
<br>
<br>
The example below shows a bend track applied to a tube object with bend
angles going from 0 to 270
degrees and back to 0 with interpolating smoothing.<br>
<br>
<table>
<tbody>
<tr>
<td><img src="animation/bend_ex_graph.jpg"></td>
<td><img src="animation/bend.gif"><br>
</td>
</tr>
</tbody>
</table>
<br>
<br>
<br>
<a name="custom"><b><font color="#3393d2">CUSTOM
DISTORTION TRACK</font></b></a><br>
<br>
The custom distortion track is the most flexible of them. Indeed, the
bend, scale and twist tracks
could all be achieved using the custom track.<br>
<br>
To add a custom track to an object, select the object and click on <b>Animation
-&gt; Add Track to Selected Objects -&gt; Distortion -&gt;
Custom </b>. This adds a track called 'Deform' to that object's
track list. The distortion operation is achieved through the procedure
editor (familiar from procedural
textures and procedural position/rotation tracks). To open the editor,
double-click on the 'Deform' track
name in the list or click right on it and select <b>Edit Track</b>.
This will display the usual procedure
editor which has outputs to x, y, and z. These are surface distortions
in those respective axes. The
insert menu contains the usual values, functions, patterns etc.
discussed in the section on <a href="textures.html#proc_tex">Procedural
Textures</a>.<br>
<br>
To better illustrate the use and power of the custom distortion track,
we'll consider an example. The aim
is to produce a 'bulge' track for a cylindrical-type object. The track
will cause the middle of the
object to 'bulge out' while the ends will remain static.<br>
<br>
First, to create a suitable object. To ensure we have a reasonable
density of vertices on the surface,
we'll use an extruded filled polygon instead of a straight cylinder.
Double-click the polygon icon and
change the number of sides to 8 and the shape to approximating to give
a virtually circular cross-section.
Whilst holding &lt;shift&gt; and &lt;ctrl&gt; drag out
a polygon in the top view window. Now click on <b>Tools
-&gt; Extrude</b>, set to extrude in the y-axis to a suitable
height and set the number
of segments to, say 10.<br>
<br>
Add a custom distortion track to the object and open up the procedure
editor. The basic algorithm for
the bulge is scale the x and y axes by a bulge factor but only within a
defined height or width. Outside
this bulge height, the scaling will be unaffected. Here is the
procedure that does this:<br>
<br>
<table>
<tbody>
<tr>
<td><img src="animation/dist_cust_proc.jpg"></td>
<td><font face="tahoma" size="2">It
looks a little complicated but really it's quite simple.<br>
<br>
First of all, there are 2 parameters that have been set up: <b>bulge
height</b> which defines the length
of the object affected and <b>bulge size</b> which is the
scaling applied to that part of the object as below:<br>
<br>
<img src="animation/bulge_diagram.jpg"><br>
<br>
The bulge is going to be centred on the object's y-axis, i.e. at y=0.
The first function is '&gt;'; this
returns 1 where the magnitude of y is less than the <b>bulge
height</b> and 0 elsewhere. This is fed into
the scaling function expression where it is multiplied by <br>
<b>(1 + bulge size)*x</b>. Thus the value of this
expression for the part of the surface outside the <b>bulge
height</b> is 0. However, we want
to scale the surface at this part of the object by a factor x, not 0,
hence the + function. This adds
onto the scaling factor another expression which is equal to x for the
part of the surface outside of
the bulge height.<br>
<br>
Inside the bulge region, the scaling factor is simply <b>(1 +
bulge size)*x</b>; the value
of the second expression is 0 inside the bulge height so it doesn't add
anything onto the first
expression. <br>
<br>
This is repeated for the z-direction with 2 expressions with x simply
substituted with z.<br>
<br>
To set an acceptable range of values and a default value for the
parameters <b>bulge height</b> and <b>bulge size</b>,
double-click the modules and enter the values. </font></td>
</tr>
</tbody>
</table>
<br>
<table>
<tbody>
<tr>
<td><font face="tahoma" size="2">The <b>Edit</b>
menu at the top of the procedure editor contains an Undo/Redo facility
and a control
on the properties of the track as shown on the right:<br>
<br>
The <b>Parameter Smoothing Method</b> is the type of
smoothing used between keyframed values of the parameters. See <a href="#pos_track_op">earlier</a> for a full
description of these smoothing types.<br>
<br>
The <b>Coordinate System</b> can be set to either <b>Local</b>
or <b>World</b> to use either the object's
own coordinate system or that of the scene. </font></td>
<td><img src="animation/cust_proc_prop_menu.jpg"></td>
</tr>
</tbody>
</table>
<br>
<br>
Because we used parameters in the expression, it is now possible to
keyframe the track. To do that,
move time marker to 0, highlight the Bulge track and select <b>Animation
-&gt; Keyframe Selected Tracks</b>.
This adds a keyframe at time 0. Repeat this at another time. To set the
parameter values for each
keyframe, double-click the keyframe to display the keyframe dialogue
window as below:<br>
<table>
<tbody>
<tr>
<td><img src="animation/dist_cust_key_dial.jpg"></td>
<td><font face="tahoma" size="2">This
dialogue lists all procedural parameters at the top with slider bars
allowing their values to be
set for that particular time.<br>
<br>
If the <b>Parameter Smoothing Method</b> was set to either
<b>Interpolating</b> or <b>Approximating</b>
in the track properties then the <b>Smoothness</b> can be
set in this
dialogue and can be made different for the interpolations before and
after this timepoint.<br>
<br>
This is the final animation made by setting 4 keyframes and varying
only the <b>bulge size</b>
parameter.<br>
<img src="animation/CUSTOM.GIF"> </font></td>
</tr>
</tbody>
</table>
<br>
<br>
Below is another example animation using the sine function to distort
the surface of flattened sphere
mesh and varying the phase of the sine wave with time. The value in
front of the x (3 in this case)
defines the number of complete sine waves within a certain distance.
The number in front of the t
controls the speed of movement of the sine wave. In this example, this
was equal to 2 x PI (6.283)
i.e. one complete cycle per second.<br>
<img src="animation/cust_dist_proc.jpg"><img src="animation/distort.gif"><br>
<br>
Custom distortion tracks can also use images to create interesting
geometries such as in the landscape example below:<br>
<br>
<img src="animation/cust_land_proc.jpg"><img src="animation/custom_landscape.jpg"><br>
<br>
Be warned, though, that a complex image such as this requires a fine
mesh to be accurately
represented and this in turn requires significant memory.<br>
<br>
<br>
<a name="scale"><b><font color="#3393d2">SCALE
TRACK</font></b></a><br>
<br>
The Scale track scales the object along any or all directions. To add a
Scale track to an object,
select the object and choose <b>Animation -&gt; Add Track to
Selected Objects -&gt; Distortion -&gt; Scale</b>.
Double-clicking the Scale track in the list on the score displays the
following dialogue window:<br>
<br>
<table>
<tbody>
<tr>
<td><img src="animation/scale_track_dial.jpg"></td>
<td><font face="tahoma" size="2">The <b>Track
Name</b> can be altered to anything you like.<br>
<br>
The <b>Smoothing Method</b> is the way in which the
scaling factors are interpolated between keyframes.
The options here are the same as described <a href="#pos_track_op">above</a>.<br>
<br>
The <b>Coordinate System </b> determines whether the <b>Local</b>
coordinate system or the <b>World</b>
coordinate system is used. If the latter is used, the object is scaled
with respect to the axes passing through
the scene origin rather than that passing through the object's centre. </font></td>
</tr>
</tbody>
</table>
<br>
<br>
To set the scaling factor at a particular time, move the time marker to
that time and select
<b>Animation -&gt; Keyframe Selected Tracks </b>. This
adds a keyframe to the score at that time. Double-click
the keyframe to set the values through the following dialogue:<br>
<br>
<table>
<tbody>
<tr>
<td><img src="animation/scale_keyframe_dial.jpg"></td>
<td><font face="tahoma" size="2">The
scaling factors are set explicitly in the <b>X-Scale</b>, <b>Y-Scale</b>,
<b>Z-Scale</b> boxes.<br>
<br>
If either <b>Interpolating</b> or <b>Approximating</b>
smoothing was set in the track options dialogue, then
it is possible to set the smoothness and to separate the smoothnesses
of the interpolation before and
after the point in time. </font></td>
</tr>
</tbody>
</table>
<br>
<br>
<a name="shatter"><b><font color="#3393d2">SHATTER
TRACK</font></b></a><br>
<br>
The Shatter track is a way of representing an explosion. The object is
broken up into triangular
fragments which move outwards as a result of the 'explosion'. The
fragments spin, are affected
by the force of gravity and can be made to disappear with time.<br>
<br>
To add a Shatter track to an object, select the object and choose <b>Animation
-&gt; Add Track to
Selected Objects -&gt; Distortion -&gt; Shatter </b>.
There are no keyframes with this type of track - all
of the controls are in the track options dialogue accessed by
double-clicking the track name in the
list of tracks on the score. The dialogue looks similar to that below:<br>
<table>
<tbody>
<tr>
<td><img src="animation/shatter_track_dial.jpg"></td>
<td><font face="tahoma" size="2">The <b>Track
Name</b> can be altered to whatever you like and appears in the
track list.<br>
<br>
The <b>Start Time </b> is the time at which you want the
explosion to begin. The track has no effect
until that time.<br>
<br>
<b>Maximum Fragment Size</b> - The fragments are all
the same size. There is no minimum size as AoI subdivides
the surface triangles until the required size is reached (note,
however, that performance is
affected as the fragment size decreases). There is a maximum size,
however, depending on the surface
geometry. A cube, for instance, can have larger fragments than a sphere
because a cube's surface can be represented by larger triangles whilst
still maintaining the required surface accuracy. This option allows
you to restrict the size of the fragments for such objects.<br>
<br>
<b>Explode Speed</b> is the initial speed at which
the fragments move outwards.<br>
<br>
<b>Fragment Spin Rate</b> determines how fast the
fragments spin.<br>
<br>
<b>Disappearance Time</b> - If this is set to
anything other than 0, the fragments will disappear at
random over time. The time set here is that at which all fragments will
have disappeared.<br>
<br>
<b>Gravity</b> sets the magnitude of the force acting
on the fragments.<br>
</font></td>
</tr>
</tbody>
</table>
<br>
<br>
<b>Gravity Axis</b> defines in which direction the
'Gravity' force acts. Normally, of course, this would
be set to Y, but this does not necessarily have to be the case.<br>
<br>
The <b>Randomness</b> defines the uniformity of movement
during the explosion. A value of 0 means an even
spread of fragments and 1 is a very random one.<br>
<br>
The <b>Coordinate System</b> is either the object's own
(Local) or that of the scene (World). With the latter
option set, the explosion will be outwards from the scene origin
resulting in a 'sideways blast' if the
object is not positioned at the origin.<br>
<br>
Below is an example of the Shatter track applied to a disc. The <b>Start
Time</b> was set to coincide with
the time at which the ball hits the disc. Approximating smoothing was
used on the disc mesh which results
in smoothed triangle fragments being created.<br>
<br>
<img src="animation/explode.gif"><br>
<br>
<br>
<br>
<a name="twist"><b><font color="#3393d2">TWIST
TRACK</font></b></a><br>
<br>
The Twist distortion track rotates the surface around a particular axis
by an angle that increases
with distance along that axis. One end of the object remains static
whilst the other twists around.
To explain this better, here is an example:<br>
<br>
<table>
<tbody>
<tr>
<td width="500"><font face="tahoma" size="2">The object used in this example is a pyramid
created by extruding a flat spline and then scaling the extruded
vertices down to a point. In order to get a smoother distortion, the
mesh was subdivided a couple
of times to give the mesh see on the right: </font></td>
<td><img src="animation/twist_obj.jpg"></td>
</tr>
</tbody>
</table>
<br>
<br>
To add a Twist track to an object, select <b>Animation -&gt;
Add Track to Selected Objects -&gt; Distortion -&gt;
Twist</b>. To edit the track options, double-click on the track
name on the score or click right on it
and select <b>Edit Track</b>. This displays the dialogue
shown below:<br>
<table>
<tbody>
<tr>
<td><img src="animation/twist_track_dial.jpg"></td>
<td><font face="tahoma" size="2">The <b>Track
Name</b> can be altered to anything you like.<br>
<br>
The <b>Smoothing Method</b> is the way in which the values
of twist are interpolated between keyframes.
The options here are the same as described <a href="#pos_track_op">above</a>.<br>
<br>
The <b>Twist Axis</b> is the axis around which the object
is twisted<br>
<br>
<b>Reverse Twist Direction</b> twists the object the
opposite way so that the other end is static.<br>
<br>
The <b>Coordinate System </b> determines whether the <b>Local</b>
coordinate system or the <b>World</b>
coordinate system is used. If the latter is used, the object winds
itself around the axis passing through
the scene origin rather than that passing through the object's centre. </font></td>
</tr>
</tbody>
</table>
<br>
To set values of Twist, select the Twist track, move the time marker to
the required time on the score
and select <b>Animation -&gt; Keyframe Selected Tracks </b>.
This produces a keyframe at the specified time position. To set the
value, edit the keyframe by double-clicking it. This displays the
dialogue
shown below:
<br>
<table>
<tbody>
<tr>
<td><img src="animation/twist_key_dial.jpg"></td>
<td><font face="tahoma" size="2">The <b>Twist
Angle</b> controls the amount of rotation around the specifed
axis at the given <b>Time</b>.<br>
<br>
If either <b>Interpolating</b> or <b>Approximating</b>
smoothing was set in the track options dialogue, then
it is possible to set the smoothness and to separate the smoothnesses
of the interpolation before and
after the point in time. </font></td>
</tr>
</tbody>
</table>
<br>
In the example below, the twist angle was varied through 5 keyframes in
a sine wave type pattern
to produce the animation shown:<br>
<br>
<table>
<tbody>
<tr>
<td><img src="animation/twist_curve.jpg"></td>
<td><img src="animation/twist.gif"></td>
</tr>
</tbody>
</table>
<br>
<br>
<a name="IK_track"><b><font color="#3393d2">INVERSE
KINEMATICS TRACK</font></b></a><br>
<br>
Inverse Kinematics Tracks allow meshes to be deformed by adding
constraints to the joints of the mesh's skeleton. Each bone joint can
either be locked or forced to follow another object in the scene.<br>
<br>
To add an Inverse Kinematic track to a mesh object, select the object
and go to <b>Animation -&gt;
Add Track to Selected Objects -&gt; Distortion -&gt; Inverse
Kinematics</b>. IK tracks do not have keyframes; rather the joint
constraints that are set apply according to the track's <a href="animation.html#track%20weight">weight</a>. The
constraints are set via the IK Track dialogue
displayed by double-clicking on the track's name on the score (or right
clicking and selecting <b>
Edit Track...</b>). This dialogue, shown below left, lists the
constraints that have been set; to add a new constraint,
click on <b>Add...</b> to display another dialogue like
that shown below right. From here you can
select a bone joint and either lock it in place within the skeletonby
clicking on the <b>Locked</b> radiobox or get it to follow
another object from the scene by clicking on <b>Follows Target</b>
then
clicking on <b>Set</b> to choose the appropriate object.<br>
<br>
<img src="animation/IK_track_dial_gen.jpg"><img src="animation/IK_track_constraint_menu.jpg"><br>
<br>
<br>
In the example below, the character's head is made to follow the 'bee'
throughout its motion. The 'neck lock'
bone joint is set to be locked and the 'head control' is set to follow
the 'bee' (in this case, the 'head
control' bone has also been locked, through the mesh editor, with
respect to its parent).<br>
<img src="animation/IK_track_skel.jpg">
<img src="animation/IK_track_dial.jpg"><img src="animation/IKtrack.gif"><br>
<br>
Sometimes you might find that the distortion caused by this type of
track creates 'squashing' of the
mesh surface. Take the example below. The undistorted mesh surface and
its simple skeleton are shown below left. In this example, the IK
constraints are set so as to lock the bottom of the mesh via the root
joint and have the joint at the top of the mesh follow a null as shown
in the IK constraint dialogue below. The null has been keyframed to
move in a roughly semicircular path around the top of the mesh. The
result shown at one particular frame is shown below, and the animation
formed from this setup is shown below right. As can be seen, the mesh
squashes unacceptably at the bend position.<br>
<br>
<img src="animation/IK_con_ex2.jpg"><img src="animation/IKtest_no_gestures.gif"><br>
<br>
To avoid this effect, we can use the 'Use Gestures to Shape Mesh'
option on the IK constraint
track dialogue. Switching this option on will make the IK constraint
track use existing
gestures to control the shape of the mesh instead of it just being
shaped by movement of the skeleton.
So what we can do in this case is to create two new gestures with the
mesh skeleton bent to each side. When creating these gestures you will
find that, as the skeleton is bent down into the appropriate position,
the mesh squashes just like it did with the IK constraint track above
(that's because it's doing exactly the
same thing). But now, we can move vertices in the gesture around to
'unsquash' the joint as shown in the
two gestures below. Now we can go back to the IK constraint dialogue
and switch on 'Use Gestures to Shape Mesh'.
Now the IK track will adjust the skeleton based on the constraints we
have set, as before. But this time it
will look at the gestures that have been created and will produce a
pose from them whose skeleton configuration
matches that of the IK constrained skeleton. This produces much better
and more controllable distortions
when using IK constraint tracks as shown in the animation below:<br>
<br>
<img src="animation/IK_con_ex3.jpg"><img src="animation/IKtest_with_gestures.gif"><br>
<br>
In actual fact, the 'Use Gestures to Shape Mesh' option doesn't care
how the skeleton gets into a
particular configuration; it doesn't have to be through an IK
constraint - it could be as a result of
a pose track or a combination of pose tracks. In this case, you may not
even want or need to set any IK
constraints; just switch the 'Use Gestures to Shape Mesh' on.<br>
<br>
The 'Use Gestures to Shape Mesh' option could also be used to create
other effects like bulging
muscles when limbs flex etc.<br>
<br>
<br>
<br>
<br>
<a name="skel_shape"><b><font color="#3393d2">SKELETON
SHAPE TRACK</font></b></a><br>
<br>
<br>
The Skeleton Shape is a method of posing a mesh with a skeleton that is
an alternative to a Pose
Track for this type of object. Skeleton Shape tracks can have keyframes
which define the configuration of the skeleton at a particular point in
time.<br>
<br>
To use a Skeleton Shape track, add one to your skeleton-containing mesh
via <b>Animation -&gt;
Add Tracks to Selected Object -&gt; Distortion -&gt; Skeleton
Shapes</b>. Add a keyframe at the appropriate
time on the Score by moving the time marker to that time and selecting <b>Animation
-&gt; Keyframe
Selected Tracks</b>. Then the keyframe can be edited by
double-clicking on it to display a dialogue similar
to that shown below:<br>
<br>
<table>
<tbody>
<tr>
<td width="300"><font face="tahoma" size="2">The editor is similar to the mesh editor except
that manipulations can be made to the mesh only via
the skeleton and not the mesh vertices. The <b><font color="#000080">Edit</font></b> menu allows one
level of Undo. <b>Edit -&gt;
Properties</b> displays the Properties dialogue which allows
left/right smoothnesses to be set as per <a href="animation.html#pos_key_edit">other tracks</a>.<br>
<br>
The <b><font color="#000080">Skeleton</font></b>
menu is shown on the image on the right: <br>
<br>
<b>Edit Bone</b> accesses the bone joint
editor (see <a href="object_types.html#skeletons">here</a>).<br>
<br>
<b>Reset to Default Pose</b> puts the keyframe's
skeleton back into the Default Pose configuration for that object.<br>
<br>
<b>Create Pose from Gestures</b> displays the current
list of gestures (the option will not be available if the
object is not an Actor) and allows the Skeleton Shape keyframe to be
created effectively from a custom pose
made up from a sum of various weightings of gestures.<br>
<br>
The <b><font color="#000080">View</font></b>
Menu is identical to the equivalent menu in the mesh editor. <br>
</font></td>
<td><img src="animation/skel_shape_key_dial.jpg"></td>
</tr>
</tbody>
</table>
<br>
The Skeleton Shape tracks can be edited by double-clicking the track's
name in the Score or right-clicking
and selecting <b>Edit Track</b>. This displays the
dialogue below:<br>
<br>
<table>
<tbody>
<tr>
<td><img src="animation/skel_shape_track_dial.jpg"></td>
<td><font face="tahoma" size="2">The <b>Track
Name</b> is editable as with other tracks as is the <b>Smoothing
Method</b>.<br>
<br>
The <b>Use Gestures to Shape Mesh</b> is analogous to the <a href="animation.html#IK_track">Inverse Kinematic</a>
distortion tracks. The Skeleton Shape tracks distort a mesh based only
on skeleton
movement. In some situations, relying on skeletal deformation alone can
lead to problems with
the mesh becoming 'squashed' - this is particularly common around some
joints, for example. However, if
you create a gesture with the skeleton in a similar configuration to
that expected to arise in the Skeleton Shape track, the vertices of the
mesh can be moved to smooth out these problems for that gesture. Then,
switching on <b>Use Gestures to Shape Mesh</b> for the
Skeleton Shape track will automatically sort out these problems.
Indeed, if you create a Skeleton Shape keyframe and edit it with this
option switched on (with appropriate gestures created), the
'unsquashing' effect is actually applied in real
time. </font></td>
</tr>
</tbody>
</table>
<br>
Below is a practical example. Here is an arm which needs to be bent at
the elbow. If we just rotate
the appropriate bone, there are problems with 'squashing' around the
joint as shown below left. If we tried to bend the arm in this way with
a Skeleton Shape track, the results
would not be acceptable. However, we can first create a gesture with
the skeleton in this position and fix the problem vertices as shown
below right. Also note, that we can move other vertices to improve
the realism, such as 'bulging' the bicep slightly and sharpening the
point of the elbow.<br>
<br>
<img src="animation/skel_shape_gests.jpg"><br>
<br>
If we now create a Skeleton Shape track with <b>Use Gestures to
Shape Mesh</b> on, create a keyframe, edit it and move the elbow
joint, the problems areas do not occur - they are corrected in real
time - together with the bicep bulge and pointy elbow. Below shows the
rendered animation between 2 keyframes
without 'Use Gestures...' (below left) and with 'Use Gestures...'
(below right).<br>
<br>
<img src="animation/arm_SS_noGest.gif"><img src="animation/arm_SS.gif"><br>
<br>
It can be seen that, using this approach, the Skeleton Shape track is a
straightforward way of keying
the primary movement of a character. A set of gestures (first convert
the mesh to an Actor via <b>Object -&gt; Convert to Actor</b>)
can be set up for the important and troublesome areas such as joints
or places where, for example, muscular movement would result in a mesh
deformation on top of the main
joint movement. The Skeleton Shape track can then be used to edit the
character's position without
further worry about 'squashing' joints etc.<br>
<br>
Note that Skeleton Shape tracks are absolute and so override other
Skeleton Shape tracks or Pose tracks
below then in the Score. A Skeleton Shape track would normally be used
to define the broad motion of a
character and relative Pose Tracks could then be used to add additional
or secondary motions.<br>
<br>
<br>
<a name="constraint_tracks"><strong><font color="#ff6633" size="4">6.2.5 Constraint Tracks </font></strong></a><br>
<br>
Constraint Tracks are unlike the other tracks that can be created in
that they do not have keyframes. They are a way of constraining the
various transformations of an object during the whole animation.
Constraint
Tracks are added to an object by selecting <b>Animation
-&gt;Add Track to Selected Objects </b> and choosing
<b>Constraint</b>. Double-clicking the relevant track name
in the list on the score displays the following
dialogue:<br>
<br>
<table>
<tbody>
<tr>
<td><img src="animation/constraint_track_dial.jpg"></td>
<td><font face="tahoma" size="2">Below
the editable <b>Track Name</b>, there are 3 rows that
define the way the object is positionally constrained. For each axis,
the <b>Constraint</b> can be selected as <b>None</b>,
<b>Less Than</b>, <b>Equal to</b> or <b>Greater
Than</b> the value (in units) defined. Setting the X-Constraint
to be <b>Less Than</b> 3, for example, means that the
object will never go beyond the plane x=3.<br>
<br>
The <b>Orientation</b> is constrained by the next section.
Here you can specify that one axis (in the
objects coordinate system) either <b>Faces Toward</b> an
object (or one of the joints of its skeleton if
it has one) of your choice selected by clicking the <img src="animation/anim_set.jpg"> button, or can be set to be <b>Parallel
to</b> or <b>Perpendicular to</b> a
vector set in the x,y and z boxes which then appear as below:<br>
<img src="animation/constraint_dial2.jpg"> </font></td>
</tr>
</tbody>
</table>
<br>
<br>
One possible use of Constraint tracks is in controlling the eye
rotation of an animated character. In
the example below, Constraint tracks were applied to both eyes to make
them face towards the swinging
gem object:<br>
<img src="animation/constraint_ex_dial.jpg"><img src="animation/eye.gif">
<br>
<br>
<a name="visibility_tracks"><strong><font color="#ff6633" size="4">6.2.6 Visibility Tracks </font></strong></a><br>
<br>
Visibility tracks are the simplest tracks available. They control when
objects become visible in the
scene. To add a visibility track, select <b>Animation -&gt;
Add Track to Selected Objects</b> and select
<b>Visibility</b>.<br>
<br>
To hide the object, move the time marker to the appropriate point in
time and either
select <b>Object -&gt; Hide Selection</b> and then <b>Animation
-&gt; Keyframe Modified Tracks of Selected
Objects </b> or select <b>Animation -&gt; Keyframe
Selected Tracks</b>, click on the new keyframe and select
<b>Animation -&gt; Edit Keyframe</b> to display the
dialogue below:<br>
<table>
<tbody>
<tr>
<td><img src="animation/visib_track_dial.jpg"></td>
<td><font face="tahoma" size="2">Here,
you can set the object to be visible or not and the time. </font></td>
</tr>
</tbody>
</table>
<br>
<br>
<br>
<a name="anim_textures"><strong><font color="#ff6633" size="4">6.2.7 Animating Textures </font></strong></a><br>
<br>
Textures can be animated in a number of ways with Art of Illusion. Two
of the methods require the use of <a href="textures.html#proc_tex">Procedural
Textures</a>.<br>
<br>
The first method uses the <b>Time</b> parameter available
in the procedural
texture editor which can be added to a texture by selecting <b>Insert
-&gt; Values -&gt; Time</b>. At any point
in the animation, this parameter is equal to the time at that point.
Therefore creating a texture which
uses the Time parameter will vary accordingly.<br>
<br>
Below is an example of a simple texture within which the Transparency
is controlled with the Time
parameter as shown:<br>
<img src="animation/tex_param_time.jpg"><img src="animation/textrans.gif"><br>
<br>
<br>
The other method is through the use of <a href="textures2.html#tex_param">texture parameters</a>.
The value of any such parameters defined in a procedural texture can be
varied with time to form an
animated texture.<br>
<br>
Having created a texture with texture parameters and assigning it to
the object, set up a <b>Texture Track</b> by selecting <b>Animation
-&gt; Add Track to Selected Objects -&gt; Texture Parameter</b>.
Double-clicking on this track in the score produces the following
dialogue:<br>
<table>
<tbody>
<tr>
<td><img src="animation/anim_tex_options.jpg"></td>
<td><font face="tahoma" size="2"> <b>Track
Name</b> is the name of the track which can be changed to
anything you like.<br>
<br>
<b>Smoothing Method</b> is as defined <a href="#pos_track_op">above</a>. In this case the
values of the
parameters are smoothed as specified.<br>
<br>
In the area below is a list of all the currently defined texture
parameters in the object's texture.
Here you can select which parameters to control via this animation
track. Multiple selections are made
by holding down the &lt;shift&gt; key while clicking on entries
in the list. </font></td>
</tr>
</tbody>
</table>
Once the parameters to be controlled have been defined, the track can
be keyframed in the normal way by moving the time marker to an
appropriate point in time and clicking
<b>Animation -&gt; Keyframe Selected Tracks</b>. The
keyframe can be edited by double-clicking it on the score or by
selecting it and clicking on <b>Animation -&gt; Edit Keyframe</b>.
This
displays the following dialogue:<br>
<table>
<tbody>
<tr>
<td><img src="animation/anim_keyf_edit.jpg"></td>
<td><font face="tahoma" size="2">Listed
at the top of the window are all the parameters that were identified in
the previous
dialogue. In this example, there are 2 texture parameters called
parameter and trans. Their
values at this point in time can be altered using the slider bars or by
typing values into the
boxes.<br>
<br>
The <b>Time</b> can also be re-defined here.<br>
<br>
The remainder of the dialogue relates to smoothing before and after the
keyframe which can either
be the same or be separately defined. <b>Smoothness</b>
values are entered appropriately and
are valid if either <b>interpolating</b> or <b>approximating</b>
smoothing was selected in the
previous dialogue.<br>
<br>
The plot views can also be used to show plots of each parameter against
time. </font></td>
</tr>
</tbody>
</table>
<br>
Below is a simple example. This has a single parameter which is
controlling the length of the
'hairs' formed using displacement mapping. Two keyframes were used at
the start (0) and the end
(1) of the animation period<br>
<img src="animation/growinf_tex.jpg"><img src="animation/growing2.gif"><br>
<br>
<br>
<a name="edit_tracks"><strong><font color="#ff6633" size="4">6.2.8 Editing Tracks </font></strong></a><br>
<br>
There are several options at the bottom half of the <b>Animation</b>
menu for editing tracks.<br>
<br>
<b>Edit Track</b> is the same as double-clicking the track
name and produces a dialogue which depends
on the type of track. See the above sections for details.<br>
<br>
<b>Duplicate Selected Tracks</b> produces identical copies
of all selected tracks.<br>
<br>
<b>Delete Selected Tracks</b> and <b>Select All
Tracks of Selected Objects</b> are self-explanatory.<br>
<br>
<b>Disable Selected Tracks</b> allows you to stop any
currently selected tracks having any effect
temporarily. <b>Enable Selected Tracks</b> reverses this
operation.<br>
<br>
Texture parameter tracks can also be used to animate <a href="textures2.html#layered_tex">blending fractions</a>
for layered textures, thereby
allowing textures to be blend into each other. Blending fractions will
appear in the Texture Track option
dialogue and can be controlled in exactly the same way as other
parameters.<br>
<br>
Note that Texture Parameter tracks cannot be used to animate per-vertex
textures. This can
be achieved, however, using a Pose Track. Set up the texture in the
same way as <a href="textures2.html#tex_param">normal</a>
and assign it
per-vertex to the object as required. When the mesh is converted to an
'actor', the per-vertex texture
information will be preserved and varied for different poses at
different keyframes with interpolation
being performed between keyframes.<br>
<br>
<br>
<a name="anim_render"><strong><font color="#3300cc" size="5">6.3 Previewing and Rendering
Animations</font></strong></a><br>
<br>
<br>
<br>
<a name="prev_anim"><strong><font color="#ff6633" size="4">6.3.1 Previewing Animations </font></strong></a><br>
<br>
<br>
At the left side of the score are the playback controls:
<p>
<img src="animation/playback.png">
<p>
Press the center button to start and stop animating the scene.  The left and right buttons jump to the time of the
very first or very last keyframe on any object.  You can adjust how quickly the animation plays by dragging the slider.
<p>
If you want more precise control over how the animation is previewed, you can use the <b>Animation -&gt; Preview Animation</b>
command.  This displays a dialogue similar to that below:<br>
<table>
<tbody>
<tr>
<td><img src="animation/prev_anim_dial.jpg"></td>
<td><font face="tahoma" size="2">The <b>Camera</b>
drop down menu allows you to view the preview from any camera that
exists in the scene.<br>
<br>
The <b>Display Mode</b> drop down menu allows you to
select the type of display for the preview from Wireframe, Shaded,
Smooth or Textured.<br>
<br>
The <b>Start Time </b> and <b>End Time</b>
specify the time period over which the preview will play.<br>
<br>
The <b>Width</b> and <b>Height</b> are the
dimensions in pixels of the preview window.<br>
<br>
The <b>Frames/sec</b> controls the smoothness of the
preview; the higher the number of frames per second, the more
interpolated positions are created and the smoother the animation
becomes. </font></td>
</tr>
</tbody>
</table>
Clicking OK the displays the preview in the selected display mode as in
the example below:<br>
<img src="animation/prev_anim.jpg"><br>
The Time and Frame numbers are displayed for reference. Click on Done
when finished.<br>
<br>
<br>
<br>
<a name="render_anim"><strong><font color="#ff6633" size="4">6.3.2 Rendering Animations </font></strong></a><br>
<br>
Animations are rendered in the same way as with still images via <b>Scene
-&gt; Render Scene</b>. This
produces the dialogue described in the chapter on <a href="rendering.html">rendering</a>. The relevant
part of this dialogue for rendering animations is shown below:<br>
<table>
<tbody>
<tr>
<td><img src="animation/render_anim_dial.jpg"></td>
<td><font face="tahoma" size="2">To
render an animation rather than a still, click on the <b>Movie</b>
radiobox.<br>
<br>
You can then specify the <b>Start Time</b> and <b>End
Time</b> over which to render.<br>
</font></td>
</tr>
</tbody>
</table>
<br>
The <b>Frames/sec</b> controls the smoothness of the
animation; the higher the number of frames per second, the more
interpolated positions are created and the smoother the animation
becomes (but the longer it takes to render and the more diskspace is
used).<br>
<br>
<b>Images/Frame</b> allows the production of a number of
images for each frame to simulate motion
blur which occurs in real life when objects are moving faster than the
camera exposure time. For each frame, the specified number of images is
produced by interpolating additional time points
and the average of the images is calculated and stored. Below is an
example; the left image has 1
image/frame (i.e no motion blur) and the image on the right has 3. The
greater the number of frames, the smoother the blurring will appear but
at the cost of speed.<br>
<br>
<img src="animation/no_mb.gif"><img src="animation/mb.gif"><br>
<br>
After clicking OK, the image file format and quality dialogue below is
displayed as below:<br>
<br>
<table>
<tbody>
<tr>
<td><img src="animation/save_options.jpg"></td>
<td><font face="tahoma" size="2">The <b>Quality</b>
determines the amount of compression in the image. A high Quality value
will look
better but will result in a larger file size.<br>
<br>
If you select either TIFF, JPEG, PNG, BMP or HDR the animations will be
saved as individual frames in the specified
image format. Selecting one of these and clicking OK will display the
filename dialogue. Each frame rendered as part of the movie will have
the filename you enter here with an extension relating to the frame
number, e.g. filename0001, filename0002 etc.. The starting number can
be changed via the dialogue
shown on the left; the default value for this is calculated according
to the start time.<br>
<br>
Alternatively, animations can be produced in the Quicktime format by
selecting the appropriate option.
Note that you need to have Java Media Framework installed for this to
work. See the <a href="installation.html">Installation</a>
page
for details. </font></td>
</tr>
</tbody>
</table>
<br>
<br>
<br>
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