Aligning the Biped to the Model

Adjusting the Biped to the Model

Adjusting Envelopes

 

Autodesk 3ds Max Tutorials > Character Animation Tutorials > Adjusting the Biped to the Model > 

Applying the Physique Modifier

After the biped is posed to match the character mesh, you apply the Physique modifier to the character mesh and associate it with the biped. The Physique modifier makes it possible to control the mesh with the biped's motion.

The Physique modifier makes the biped act as a skeleton under a mesh “skin”. Physique assigns each vertex in the mesh to one or more bones in the biped. When the biped bones are animated, appropriate vertices in the mesh will move along with each biped part.

The process of applying and adjusting Physique is called skinning.

Set up for this lesson:

1. Load the file my_wilson_pose.max that you created in the lesson Aligning the Biped to the Model . Alternatively, you can load the file physique_wilson_start.max from the \tutorials\character_animation\physique_basics directory.

   

   This scene contains the character Wilson and a completely posed biped.

   You'll apply the Physique modifier to Wilson's head and body, but not his eyes or hair. You'll deal with those objects in a different fashion later on.

   In general, the skinning process is easiest when models are as low-poly as possible. Both Wilson's head and body have been smoothed with the MeshSmooth modifier. If you were applying Physique to just one of these objects, you could simply apply it below the MeshSmooth modifier on the modifier stack. Because you'll be applying it to two objects at the same time, you'll need to remove MeshSmooth from both objects and reapply it later.

2. Select the object Wilson Mesh Body.
3. Open the Modify panel.
4. Highlight the MeshSmooth modifier on the modifier stack, and click Remove Modifier From The Stack.
5. Select Wilson Mesh Head and remove the MeshSmooth modifier from its stack.

Turn on Figure mode:

1. Press the H key and select Wilson Biped. This selects the biped's center of mass.
2. Open the Motion panel.
3. If Figure mode isn't already on, turn it on.

Apply Physique:

You apply Physique as you would any modifier in 3ds Max.

1. Select the objects Wilson Mesh Body and Wilson Mesh Head.
2. On the Modify panel, choose the Physique modifier from the Modifier List to apply it to the selection.

   The Physique modifier appears on the stack in italics to indicate that it is instanced (applied to more than one object at a time).

Attach the biped and mesh:

1. In the Front viewport, zoom in on the biped's center of mass.
2. On the Physique rollout, click Attach To Node.
3. In the Front viewport, click the biped's center of mass.

   The Physique Initialization dialog appears.

4. Click Initialize on the dialog.

   

   An orange skeleton line appears throughout the mesh. If Physique has been properly applied, the line should extend up through the head, down through all the fingers and through to the ends of the toes

   If the orange skeleton line does not go to the ends of the head, fingers, and toes, this means you picked an object other than the center of mass after clicking Attach To Node. If this happens, click Attach To Node and repeat the last few steps until the orange skeleton line appears correctly.

Create a test animation:

Physique assigns vertices to specific biped bones based on the size of each bone and its proximity to vertices. With careful posing of the biped, the default assignments can be quite accurate, but some adjustment is always needed.

The fastest way to check vertex assignments is to make a simple animation with the biped and watch how the mesh responds. You'll hide the mesh while animating the biped to minimize the distraction.

1. Select the named selection set Wilson Mesh, and hide the selected objects.
2. Select any part of the biped and go to the Motion panel.
3. Turn off Figure mode.
4. Expand the Key Info rollout. At frame 0, select the biped's upper arms and thighs, and click Set Key.
5. Go to frame 10 and turn on Auto Key.
6. Pose the biped with one arm up and one arm down, and with legs split front and back slightly.

   

7. Scrub the time slider to see the simple animation.
8. Turn off Auto Key.

Check the default vertex assignment:

1. Go to frame 0.
2. Unhide the mesh.
3. Scrub the time slider to see how well the mesh responds to the animation.

   

   A few difficulties are immediately apparent:

   • Parts of the pant legs are left behind when the legs move.
   • Parts of the sleeves are left behind when the arms move.
   • Hips are slightly crumpled.
   NoteIf you used your own version of the posed biped, your problems with the mesh might be slightly different.

   You will fix these problems by adjusting envelopes in the next lesson.

4. Save your work in the file my_physique_wilson.max.

   You'll find a finished version of this lesson in the file physique_wilson_complete.max.