INSIDE 3DS MAX® 7 [Electronic resources] نسخه متنی

Physique vs. Skin

First, a little history. When character studio first came out, there was no modifier in 3ds max that would let you drive the animation of a mesh using bones. So character studio included the Physique modifier as part of the product. The Physique modifier was added to the character mesh objects and then the Biped bones were added to the Physique modifier. Physique created a series of envelopes of influence that directed the relationship between the Biped bones and the mesh vertices.

Later versions of 3ds max added a default Skin modifier that could be used for the same purpose. This was included for competitive reasons, as other 3D programs came with this feature, and users were not required to pay extra for it. Since character studio was an additional plugin that cost extra, the Skin modifier was originally designed as a "slightly lesser-than" product with simpler UI and fewer bells and whistles.

Over time, however, Skin underwent additional changes and improvements. Vertex painting and the Skin Weight table were added, as well as the ability to mirror skin weights. Meanwhile, the original developer of the Physique module left Unreal Pictures, and development more or less ceased on Physique.

So you have a choice. You can use Physique or you can use Skin.

One advantage of Physique is that it has more control over envelope editing. This can allow you to get a better handle on your mesh deformation at the envelope level before moving on to weighting vertices. Physique also has a Bulges and Tendons editor that gives you more control over deforming the mesh.

Skin has options similar to Bulge, but the toolset is not as robust. Skin is a newer option for mesh deformation. Features such as the Skin Weight table and mirroring vertex weights are better implemented. Skin is also much more exposed to MAXScript and the custom user interface. The Skin Utils feature works well with Skin.

How to decide which to use? Generally, if you like the process of painting weights, go with Skin. If you like the closer integration with cs and the Bulge editing feature, Physique is the way to go. You may have to try both on a character to make an informed choice.

Skin Your Mesh to Biped Bones

If you are creating a character that happens to be a "hard surface" character such as a robot or a mechwarrior, you can simply use the Select and Link tools to link the mesh components directly to the Biped bones. Jointed characters also fall into this category. Make sure your mesh object's pivot points coincide with the Biped bone pivots, otherwise you can get unexpected results.

Here are the general steps you use to Skin your mesh to your Biped bones:

1.	Select your mesh object.
2.	Add a Skin modifier to your mesh object. Tip If you have multiple objects, it's a good idea to add individual Skin modifiers, rather than to use instanced Skin modifiers (one modifier added to multiple objects). Instanced Skin modifiers have reportedly been responsible for sluggish viewport performance.
3.	In the Parameters rollout of the Skin modifier, click Add to add the bones you would like to deform the mesh.
4.	Choose all the Biped bones except the COM object (usually Bip01).
5.	Animate the Biped in different poses to see how the mesh deforms.
6.	Adjust the Skin modifier's envelopes and vertex weighting so the character mesh deforms properly (Figure 15.9). Figure 15.9. Skin envelopes.

Physique Your Mesh to Biped Bones

Here are the general steps you use to Physique your mesh to your Biped bones: