Clusters made of polygons or edges are not supported for shape animation.
Shape animation (sometimes called morphing, blend shapes, or endomorph), is the process of deforming an object over time. To do this, you animate the geometrical shape (deformation) of an object using clusters of points and take “snapshots” (store shape keys) of the object in different poses, then you blend these poses to animate them. Softimage offers a number of tools in which you can create shape animation so that you can work in any way that you feel comfortable.
|
Clusters made of polygons or edges are not supported for shape animation. |
In Softimage, all shape animation is done on clusters. This means that you can create different clusters on an object and create shape keys for each of them, or you can treat a complete object as one cluster and store shape keys for it (see Choosing the Cluster for Shape Keys).
You can use surface (NURBS) or polygon objects to create shape animation, or even curves, particles, and lattices—any geometry that has a static number of points.
You can create shape keys from any kind of deformation to produce shape animation. For example, you can store shape keys for certain clusters on an object by moving points or deforming by spline, such as for facial animation and lip-syncing. Or you can create a shape key for an overall deformation of an object using envelopes, lattices, quick stretch, or weight maps. For more information on deformations in general, see Deformations
[ Modeling and Deformation Basics ].
After you’ve created your shape keys, you can animate how the shapes are weighted against each other. Softimage uses the animation mixer under the hood to blend the shapes. The mixer is a powerful tool that gives you a high degree of flexibility in creating and reworking your shape animation.
Different Tools for Animating Shapes
Shape animation in Softimage uses the animation mixer under the hood to do its work. You can also use the animation mixer to do your work with shape animation, but there are other methods too. You can:
• Use the shape manager to easily create and animate shape keys. This is probably the fastest, easiest, and most interactive way to work.
• Select shape keys from a group of target shapes (sometimes called morphing or blend shapes).
• Store and apply shape keys at different frames.
• And, of course, you can use the animation mixer. It is a powerful tool that gives you a high degree of flexibility in reworking your shape animation in a nonlinear way. Because shape animation is essentially pose-based, you can easily reorder the poses in time, add new poses, reuse the same pose several times, and mix the poses together as you like, all in the animation mixer. You can even add audio clips to the animation mixer to synchronize your shape animation to sound, such as for lip synching.
For more information on these techniques and tools, see Overview of Shape Animation Methods.
Shape Sources (Keys) and Clips
Shape keys have two parts: sources and clips.
• A shape source is a shape that you have stored and are usually referred to as shape keys. By storing several shape keys for an object, you can build up a library of sources.
Shape sources are stored only in the model’s Mixer > Sources > Shape folder; that is, they are not also stored at the scene (application) level as action sources are. This is because the shapes need to be kept directly with the object’s clusters to which they’re referring.
• A shape clip is an instance of a shape key (source) at a particular position along a track in the animation mixer. You can create multiple clips of the same source, thereby returning to the same shape several times in the same animation or rearrange the order of the shape clips on the tracks to change the shape animation completely.
Shape animation is stored for clusters, so you can have shape animation on different clusters on the same object. In the animation mixer, a separate container (compound clip) is created for each shape-animated cluster. This means you can easily manipulate the entire animation of a cluster all at once; for example, you can scale it or offset it using the compound shape clip. You can even copy a compound shape clip from one model to another.
To weight the compound clips against each other, see Weighting with Compound Clips.
If clusters overlap—that is, if certain points belong to more than one cluster—you can control the relative weight of each cluster’s animation on the shared points. See Mixing between Clusters.
For information on creating compound clips, see Combining Clips into Compound Clips.
|
• If you select a different cluster or set of points, the shape keys are stored for the other cluster and instantiated in a different compound shape clip. Use the Clusters button on the Select panel to help you select the correct cluster. • If you want clips to be linked to the scene’s time, you can give them an “infinite” time length. This is useful for shape compound clips that take the full length of the scene: when you change the start or end frame of the scene’s time, the compound shape clip reflects this change and continues to drive the geometry rather than having the geometry return to its un-shape-animated state. See Setting an Infinite Length for Clips. |
The Cluster Shape Combiner is an operator under the shape-animated object’s geometry that lets you control how much each point in a shape-animated cluster is influenced by each deformation that is applied to it. For more information, see Mixing between Clusters.
This operator is created as soon as a shape clip is created in the mixer, such as if you store and apply a shape key or bring it into the mixer to create a shape clip. It appears in the object’s Shape Modeling region of its construction history and its order is important. As a basic rule, shape animation is done on everything that’s below the Cluster Shape Combiner; the operators that are above the Combiner (in the Animation region) are used to create the relative shapes.
For more information on the Cluster Shape Combiner’s position, see Creating Shapes in Shape Modeling Mode.
Finding Shape Elements in the Explorer
While you are working with shapes, you’ll find that the explorer is a valuable tool in helping you find things in your scene. There are two main nodes to keep track of when working with shapes: the model’s Mixer node and the shape-animated object’s Geometry node.
The Mixer Node
The Mixer node is found in every model (the scene root has one too because it is also a model).
|
Select Mixers Only from the filter menu in the explorer to display only each model’s Mixer node. |
• The Sources > Shape folder contains all the shape keys (sources) that you have created for the model.
As soon as you create a shape key, a compound clip (such as Point_ClusterClip_Source as shown on the left) is created, containing all shape keys set for a cluster. See Shape Sources (Keys) and Clips for more information on sources.
• The Tracks > Shape folder contains all the shape tracks that exist in the animation mixer for the model.
Under the shape compound clip name (such as Point_ClusterClip as shown on the left), all tracks within that compound are listed.
Within each track list, there is a Clip list folder which contains each clip on each track. From there, you can access all information that is particular to each clip, such as its time control (see Changing Time Relationships (Timewarps)) and weight (see Mixing the Shapes’ Weights).
|
To open to a shape clip’s folder quickly, select the clip in the mixer and then (with the mouse pointer in the explorer) press the E (isolate) or F (frame) key. |
• Within the Tracks > Shape folder under the compound clip, there is also a Transition list folder which contains the information on any transition you’ve created between clips on tracks (standard or Cardinal), such as its weight. For more information, see Creating Transitions between Clips.
The Geometry Node
The Geometry node (in the example below, it’s the Polygon Mesh node) of the shape-animated object contains information about its clusters and the Cluster Shape Combiner.
• The Cluster Shape Combiner is an operator in the Shape Modeling region that lets you set the weight of different clusters, including overlapping clusters, as described in The Cluster Shape Combiner.
• The Clusters folder contains all clusters on the object, whether they have shape keys on them or not.
If a cluster has shape keys, you’ll see them listed below it. For example, as shown on the left, the shape keys for the cluster called left_eyebrow are frown, neutral, secondary, and surprise.
|
In the schematic view, shape-animated objects are identified with the letter S (as shown on the left). |
Selecting Only Objects with Shapes
When you have a crowded scene, it’s sometimes difficult to select only the objects you want. To select only objects that are animated with shapes, you can use a special shape filter from the Filter menu on the Select panel.
To use the selection filters
1. In the Select panel of the main command panel, click the little arrow button to open the Filter menu.
2. Select the Obj w Shapes filter.
Getting a Head Start on Facial Animation
You can get going quickly on facial animation by loading a predefined low-resolution polygon mesh head (male or female). This makes it easy to create any number of different faces with the same topology, which in turn makes it easy to copy shape keys between them.
The faces are implemented in Softimage as models. For more information about working with models in general, see Models [ Data Management ].
Face Maker
Face Maker lets you get a standard male or female head, then use sliders to control the facial features. You can create many heads, each with its own distinctive face, yet with all heads sharing the same underlying topology.
To get a face
1. Choose Get > Primitive > Model > Face - Man or Face - Woman. A face is created and the Face Maker property editor opens.
2. Use the sliders to control the size, position, and other attributes of the facial features. You can also transform and deform points and clusters manually, and still adjust the Face Maker properties.
To change Face Maker properties
The Face Maker controls are a custom property applied to the root null of the model. To display and modify these properties again at a later time:
1. Select the null root of the model.
2. Click Selection on the Select panel.
3. Click the Face_Maker icon.
Autodesk Softimage v.7.5