The following is a workflow overview of how you can build and work with muscles using the Muscle Creator window.

1. Open the Muscle Creator window and create a muscle. See Open the Muscle Creator window and Create a muscle.
2. Set/store the muscle poses for Rest, Squash, and Stretch. See Set muscle pose states.

   To do this, switch to the Edit tab and bend the actual bones/joints that the muscle is attached to into the Rest, Squash and Stretch states, then click the Set Current State As buttons for each state.

3. Go back to the default state/bone positions. Adjust the start/end locations for the muscle as well as the red cubes to set up the default spline curve for the muscle in the rest state.
4. Go to the Squash state. In this case, you can again move the control, except do not move the red square, but instead move its child: the Sq curve. This curve controls the centerline spline when the muscle is in squash.
5. Repeat using the related St curves for stretch.
   NoteYou may want to disable Jiggle during these steps so that you do not see any of the Jiggle effect.

   The way to think about this is the muscle goes through some centerline. That line is an implicit spline defined by the red boxes for Rest state, or the Sq or St curves for the Squash and Stretch states. You need to tell the muscle what state is what first, then fix or adjust those after storing the states. You must set all three states in order for state reading to work correctly.

   Adjust the cross sections for each state for actual shaping. This is similar to custom muscle shaping, except it is all exposed and you have the exact three states you want. You can also put blendShapes or rigging on the cross section curves.