Blend Shapes


Maya's blend shapes deformer lets you deform an object to match the shape of one or more objects. These target objects are usually copies of the original object, modified in specific areas. For example, you can duplicate a character's geometry, reshape the duplicate's mouth into a smile, and use it as a target object. This technique allows you to animate a smooth transition from a neutral expression to a smile. Because you can have multiple target objects, you can easily add a wink or a raised eyebrow. You can animate the influence of each target independently using the Blend Shape editor.

Blend shapes are most commonly used for facial expressions and phonemes, the mouth positions used for lip sync.

To create a blend shape:

1.

Select the object to which you want to add a blend shape.

2.

Duplicate the object by choosing Edit > Duplicate.

3.

Move the duplicate object away from the original so you can easily edit it.

4.

Modify the duplicate object's CVs or vertices to create the expression you want (Figure 13.23).

Figure 13.23. The duplicate object (right) has been modified to create a smile.


5.

Rename the object to reflect its expression.

This name will be used to label the target object's slider in the Blend Shape window.

6.

Repeat steps 1-5 for as many target objects as you want to use in the blend shape (Figure 13.24).

Figure 13.24. The three target objects (right) will be hidden after the blend shape is created, so it doesn't matter that they overlap the original character (left).


7.

Select all the duplicate objects.

8.

-select the original object.

9.

Choose Deform > Create Blend Shape (Figure 13.25).

Figure 13.25. To create a new blend shape, choose Create Blend Shape from the Deform menu.


A blend shape is created for the original object, using the duplicate objects as targets.

Tips

  • You can modify a blend shape by editing any of its target objects in component mode. The blend shape automatically reflects your changes.

  • Once you've created a blend shape, you can hide or delete the target objects you used to create it. Deleting them reduces the file size and may improve manipulation speed but removes your ability to modify the blend shape.


To animate with a blend shape:

1.

Choose Window > Animation Editors > Blend Shape.

2.

Under the blend shape you want to animate, move the target slider(s) to create the pose you want (Figure 13.26).

Figure 13.26. Moving a target slider causes the object with the blend shape to deform, taking on the appearance of the associated target object.


3.

Key the target weights by clicking the Key button under each target weight you've modified, or click the Key All button on the left side of the Blend Shape editor.

4.

Move to another keyframe, and repeat steps 2 and 3 to continue animating.

Tips

  • To view a blend shape's keys in the timeline or Graph Editor, click the Select button below it in the Blend Shape editor.

  • You can multiply a target's effect by entering a value greater than 1 in its field. This creates an exaggerated effect on the object that's being influenced.


To add a target to a blend shape:

1.

Select the new target object.

This object should be based on a duplicate of the original, since target objects must have the same number of vertices.

2.

-select the object with a preexisting blend shape (Figure 13.27).

Figure 13.27. You can add additional target objects to a preexisting blend shape at any time.


3.

Choose Deform > Edit Blend Shape > Add.

The new target appears in the Blend Shape editor (Figure 13.28).

Figure 13.28. A new slider is displayed in the Blend Shape editor.





Maya 7 for Windows and Macintosh(c) Visual Quickstart Guide
Maya 7 for Windows & Macintosh
ISBN: 0321348990
EAN: 2147483647
Year: 2006
Pages: 185

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