Posing a Biped

Biped Quickstart

Animating the Biped with Freeform Animation

 

Autodesk 3ds Max Tutorials > Character Animation Tutorials > Biped Quickstart > 

Applying Physique

After the biped is posed to match the character mesh, you apply the Physique modifier to the character mesh. The Physique modifier associates the biped with the character mesh.

After Physique is applied and set up, any animation on the biped is passed on to the mesh, making it move as if there were bones and muscles underneath.

Set up the lesson:

1. Load cs4_qs_drX02.max from the tutorials\character_animation\quick_start folder.

   This scene contains Dr. X and a completely posed biped.

2. In the Front viewport, zoom in on the biped's pelvis (orange triangle) and the center of mass, or COM (blue tetrahedron).

Apply Physique:

1. Select the character mesh, DoctorX.
2. On the Modify panel, choose Physique from the Modifier List.

   The Physique rollouts appear in the command panel.

3. In the Physique rollout, click Attach To Node, then click the biped's COM.

   The Physique Initialization dialog displays.

4. Click Initialize.

   The character mesh is now associated with the biped. The orange deformation spline running through the mesh indicates that the entire biped structure has been associated with the mesh.

   

   Orange spline follows Dr. X mesh. (This view uses See-Through display mode with the biped bones hidden.)

   Tip To toggle the view to See–Through display mode, select the DoctorX mesh and press Alt+X.

Adjust the envelopes:

Physique associates the biped with the mesh via the mesh's vertices. Each biped part is surrounded by an area called an envelope, and mesh vertices that lie inside an envelope are effected by that biped part. The default size of an envelope depends on the size of the biped part, which you set when you pose the biped.

Often, envelopes need to be manually adjusted to make the biped work properly with the mesh. If you notice irregular spikes poking out from the mesh, it's a good indication that one or more vertices lie outside of an envelope's area of influence. You can see this effect by rotating the arm.

1. Right-click the Top viewport to activate it and use Region Zoom to view Dr. X's left arm.

   

2. Select DrX Biped L Forearm and rotate it up and down.

   Some vertices don't move with the arm.

   

   Vertices that are not influenced by the envelope pull out of shape.

3. Press Ctrl+Z to put the arm back to its original position so you can adjust the envelope.
4. Select the DoctorX mesh again and in the modifier stack, click the plus (+) symbol next to Physique and highlight the Envelope sub-object.

   

   Note that the orange splines running through the biped have turned yellow. These are deformation splines, which deform the mesh as the spline moves.

5. Select the deformation spline running along the biped's left forearm to display the associated envelopes.

   

   Notice that each biped part has two envelopes, an inner one (red) and an outer one (purple). Some of the vertices near the opening of the glove are outside the outer envelope boundary. These vertices won't be affected at all by the biped's lower arm unless the envelope is enlarged.

6. In the Blending Envelopes rollout, in the Envelope Parameters group, increase the Radial Scale parameter to 2.0.

   The vertices at the opening of Dr. X's glove are now within the envelope.

   

   The dark outer envelope completely encompasses the lower arm.

   Many more small adjustments are needed to make all the envelopes fit the mesh correctly. In the next lesson, you'll load a file that has a mesh with envelopes that are properly adjusted.

   NoteKeep in mind that the default envelopes are based on the size of the biped bones. Therefore, if you adjust the envelopes of a character that uses the Classic biped body type, and later change to the Skeleton body type, the envelopes are going to be much smaller and will require more editing.

   When you have finished adjusting envelopes, you can apply a MeshSmooth modifier to the mesh above the Physique modifier to make the mesh look smoother.

7. Apply the MeshSmooth modifier to the mesh above the Physique modifier, and make sure its Iterations value is set to 1.

   When MeshSmooth is placed above Physique on the stack, you only need to adjust envelopes for the low-poly version of the model. The Physique settings are passed up the stack to the MeshSmooth modifier.

8. Save your work as my_drx02.max.

   If you want to learn more about adjusting envelopes and vertex assignments, see the lesson Adjusting Envelopes .