Creating a Biped

Biped Quickstart

Applying Physique

 

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

Posing a Biped

Once you've created a biped, you need to pose it to match the character model that the biped will control. This is done in Figure mode, which allows you to bend, rotate, and scale parts of the biped to conform to the character mesh. In this lesson, you will adjust a biped to fit a character mesh.

Character meshes are usually built in one of two stances. The most common is with the arms out and the legs slightly spread, like da Vinci's drawing of the Vitruvian Man. Or, the character mesh is built in a resting position with arms at its sides and legs together.

For this lesson, you'll be working with a character named Dr. X.

Set up the lesson:

1. Reset 3ds Max.
2. Load the scene file cs4_qs_drX01.max from the tutorials\character_animation\quick_start folder.

   This scene contains a character mesh named DoctorX.

Build the biped:

Now that you know how to create a biped, you're going to use the character mesh as a template for building the biped that will control Dr. X.

1. On the Create panel, click Systems.
2. Turn on Biped and make sure you can see the Height spinner in the Create Biped rollout.
3. In the Front viewport, click down at Dr. X's feet and drag up until the biped is about 1.0m in height

   This will place the center of mass (COM) roughly at Dr. X's pelvis.

   

   The new biped and Dr. X.

4. In the Create Biped rollout, change the Root Name to Dr. X.
   NoteWhen you change the name on the Create Biped rollout, the name is used as a prefix for all the biped’s component parts; for example, Dr. X L Foot. If you use the usual Name And Color rollout, only the name of the biped’s COM is changed; all other parts remain prefixed with Biped01 (or whatever the current sequence number is).

Position the biped:

Once the biped is added to the character mesh, you need to adjust the biped to better match the stance of the mesh. First, you'll adjust the position of the biped within the Dr. X model.

1. Click the Motion panel tab.
2. In the Biped rollout, turn on Figure Mode.

   All changes to the biped's reference pose must be done in Figure mode.

3. In the Left and Front viewports, click Zoom Region and zoom in around the pelvis of Dr. X.

   The illustrations show the COM in white and arrows pointing at the center line of the mesh.

   

   Zoom into Left viewport

   

   Zoom into Front viewport

4. In the Track Selection Rollout, make sure the Body Horizontal button is active.
5. Move Dr.X, the COM, in both the Left and Front viewports so that it lines up with the vertical center line of the character mesh.

   

   Bip01 moved in the Left viewport

   

   Bip01 moved in the Front viewport

Adjust the legs:

Next, you'll adjust the legs so they conform with the character's legs. When adjusting legs, you'll want to pay close attention to the key bend points at the knees and ankles.

1. Activate the Front viewport. Enlarge the viewport by pressing Alt+W on the keyboard and click the Zoom Extents button.
2. Select the biped's left thigh, Dr.X L Thigh. This is colored blue by default, and its name appears in the name field at the top of the Motion panel when selected.

   

   TipIf you select the mesh by mistake, deselect by clicking outside the figures, and then try again.
3. From the Track Selection rollout, click the Symmetrical button.

   The biped's right thigh, Dr.X R Thigh is now added to the selection set.

   

4. In this step, you rotate the biped's legs to run roughly along the legs of the mesh. To make these rotations, you'll have to switch between the Front and Left viewports. Press F and L on the keyboard to make these switches.

   Click the Rotate button and make the following rotations:

   • In the Front viewport, rotate about 12.0 degrees about the Z axis. A readout appears in yellow as you rotate the selection.
     TipSometimes the legs will rotate in parallel, instead of in opposite directions. If this happens to you, select and rotate each leg individually.

     

   • In the Left viewport, rotate about –8 degrees about the Z-axis.

     

5. On the main toolbar, choose Select And Non-Uniform Scale. Scale the thighs along the X-axis until they match the skin model: about 85 percent. Type in the value or use the spinners while viewing the results in the viewport.

   

6. Press the Page Down key on the keyboard.

   Page Up and Page Down are quick shortcuts for moving up and down the hierarchy. Since both thighs were selected, now both calves are selected once you’ve pressed Page Down.

7. As you did with the thighs, scale the calves until they match the mesh: about 90 percent along the X axis.

   This aligns the biped's ankles more closely with the ankles of the character mesh.

   

   The Left view of the scaled thighs and calves.

8. Press Page Down again to select the biped feet. Scale the feet from the Front and Left views to more closely fit in the shoes.

   

9. On the Structure rollout, adjust the Ankle attach value to slide the foot to better fit in the mesh: about 0.1.

   

10. In the Front viewport, rotate the feet so they align with the mesh.

    

    Rotate the feet to fit the mesh.

11. Save the scene as my_drx01.max.

The procedures you've just completed give you an idea of what it takes to align a biped to a mesh, and that patience is the key to this process. This character still needs work, such as the feet need to be adjusted as well as the entire upper body. If you want, read the following tips for biped alignment, then use the same procedures to experiment with aligning the rest of the biped. Otherwise, continue to the next lesson.