Page 1023 - Kitab3DsMax

Of all the animation modifiers, several specifically are used to deal with skin. The Skin modifier is a key
modifier for enabling character animation. The Skin Morph modifier lets you deform a skin object and cre-
ate a morph target. It is designed to help fix problem areas, such as shoulders and hips, that have trouble
with the standard Skin modifier. The Skin Wrap offers a way to animate a low-res proxy and then apply the
same animation to a high-res wrapped object.
Note Animated Skin Modifiers Chapter 40: Skinning Characters
A Physique modifier left over from the Character Studio suite of tools has been integrated into Max. The Physique
modifier also is used to bind skin meshes to skeletons, but the Skin modifier is easier to use and more powerful.
The Physique modifier remains for backward compatibility. n
Understanding the skinning process
Unless you like animating using only a skeleton or a biped by itself, a bones system will have a skin
attached to it. Any mesh can be made into a skin using the Skin modifier. The Skin modifier is used to bind
a skin mesh to a bones system and to define the associations between the skin vertices and the bones. The
first step is to bind the skin mesh to the skeleton object. With a skin attached to a bones system, you can
move the bones system and the skin follows, but just how well it follows the skeleton’s motion depends on
a process called skinning.
Cross-Ref
Creating a bones system is covered in more detail in Chapter 37, “Understanding Rigging and Working with
Bones.” Bipeds are covered in Chapter 39, “Animating with CAT and Creating Crowds.” n
Skinning is where you tell which parts of the skin mesh to move with which bones. Obviously, you’d want
all the skin vertices in the hand to move with the hand bone, but the skin vertices around the waist and
shoulders are trickier.
Each skin area that surrounds a bone gets encompassed by a capsule-shaped envelope. All vertices within
this envelope move along with the bone. When two of these envelopes overlap, their surfaces blend
together like skin around a bone joint. Most of the skinning process involves getting the skin vertices into
the right envelope. The Skin modifier includes several tools to help make this easier, including the Skin
Weight table and a painting weights feature.

Binding to a skeleton
After you have both a skeleton and a skin mesh, you need to bind the skin to the skeleton before you can
edit the influence envelopes. The binding process is fairly easy: Simply select the skin mesh, and apply the
Skin modifier to it using the Modifiers ➪ Animation ➪ Skin menu command.
Tip
Before binding a skeleton to a skin mesh, take some time to match the size and dimensions of the bones close to
the skin mesh. The skin mesh is bound to the skeleton, and the envelopes are created automatically. If the bones
match the skin, then the new envelopes are pretty close to what they need to be. n
In the Parameters rollout, click the Add button above the bones list. This opens a Select Bones dialog box
where you can select the bones to use to animate this skin. The selected bones appear in the bones list. The

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