As an alternative to manually converting NURBS surfaces, you can create simple muscles using the Muscle Builder window. The following section gives an example of how to create simple muscles with the Muscle Builder window.

To build a simple muscle

1. Create some joints in the Maya scene.

   While it is not required, you should align your joint axis such that one of the local axes cleanly points down the length of the joint chain. The default for Maya is X. You can use any free joint orient tool to align your joints that way, or before creating joints, you can use the Joint Tool settings and set the Orientation to yzx and the Second axis world orientation to +y.

   Regardless, you need to know which axis you are using down the length of the joint. The Muscle Builder window is set up to expect the Y-axis down the chain, but it works with any setting. The image below shows an example of joints properly aligned with Y down the length:

   

2. Select Muscle > Simple Muscles > Muscle Builder from the main menu bar.

   The Muscle Builder window appears with the Build tab open.

   

3. In the Attach Obj 1 and Attach Obj 2 fields, enter the name of each joint or attach object. You can do this by selecting a joint, then clicking the buttons to load the object into the field. Shown below, joint1 and joint2 have been entered.

   

   In addition, you can change the nSpans and nSegs to a desired value. You can set these two values at any time, but you have to click Build/Update again to refresh the surface. All other values can be tweaked once the surface is built. See Muscle Builder window for more information on each option.

4. Click Build/Update, and a simple NURBS muscle is generated with the values that you have specified.

   

5. Adjust the settings to control where the simple muscle is placed, its overall width, and falloff scaling. You can click Attach Obj 1 or Attach Obj 2 to directly select and move the attach points of the simple muscle.

   

   Now you can work with the cross section tools to change the shape of the simple muscle.