Character Animation with 3DSMAX [10 mn de lecture - paru le 9/9/2004 11:15:25 AM - Public : Confirmé]

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Maxence MAMY Elève-Ingénieur Supinfo Paris Promotion SUPINFO 2004    Lui écrire    Tous les projets de cet auteur    Le mini-CV de cet auteur

2. The skin

Now that the mecanic is set, we need to define how skeleton will deform the mesh.

2.1. the Skin modifier

In the modification panel, select the skin modifier.

In the parameters roll out, click on Add to indicate skeleton which will deform the skin.

Click on the Selection by List tool, and choose all the bones which compose skeleton.

Now, we're going to adjust envelopes, that means which part of the mesh will be deform by the movement of bones. In the modifiers stack, develop Skin and choose Envelope.

It's possible to choose what kind of envelope do you want : rigid or deformable.

Select the bones one by one et then set the cylinders which are the envelope size. That means the volume of the mesh that will be deformed by the appropriate bone.

All part of the mesh which is in blue isn't in the envelope.

2.2. The Physique modifier

The Physicque modifier works in the same way as the skin modifier but is much more complete. If it's mainly intended for bipeds generated with character studio, physique can apply to any object or even a system of bones. It allows besides the envelopes setting, the possibility of managing bulges, tendons...

Here's a biped generated by Character Studio.

In the modifier panel, choose Physique.

In the Physique roll out, click on Attach to Biped.

Click on the Selection by List tool, then choose Bip01 or Bip01 Pelvis.

A window of initialization opens, leaving you the possibility of adjusting mesh deformation parameters.

Remark: if you modify the parameters, they are going to be applied to every bone of the biped.

To better adjust envelopes, we are going to load a motion file to apply to the biped, what is largely going to facilitate the task. Indeed, envelopes problems appear during certain movement, while they could not be detected without movement.

Into the Biped roll out click on Open

Go in the directory of Character Studio and select for example dynamic_3.bip (very particular animation making move the biped in a lot of different moves, what is going to help us to adjust envelopes).

It's possible to have preview of the movement in the small window.

By opening it, you can notice that Character Studio generates the corresponding keys in in the animation bar. We can already detect problems of envelopes in the heel and on arms.

In the modifier stack, develop Physique and click on Envelope. Concept is the same as the Skin modifier.

Select the bone which is not correctly adjusted and in the Envelope Parameters area, modify Radial Scale value, which corresponds to the beam of the cylinder forming the bone envelope, Parent Overlap value which enlarges the same cylinder towards the parent bone, and Child Overlap value which enlarges the cylinder towards the child bone.

Once all the envelopes corrected, you can play the animation and see your model following perfectly the biped.

You can also play the animation by clicking play animation in the biped panel, much performant because only bones become visible and we can so show the real-time animation without jerks.