Cinema 4D / BodyPaint 3D Program Documentation Reference Cinema 4D Cinema 4D Visualize, Broadcast, Studio Character Animation
Function available in CINEMA 4D Studio

Muscle

Basic Coord. Object Dynamics Falloff

Muscle

A new muscle system has been implemented in R13. As with the old muscles system (from Cinema 4D R11), it is based on actual muscle objects that you can shape based on their length and then add a Deformer MSkin, which will affect the geometry of your character. The logic is the same as the connection between Joint and Skin, the combination of both deforming the geometry of an object. It gives you more control over what the muscle objects should deform.

Muscles can slide under the mesh and push it, as before, but can also pull it to take into account loss of volume (particularly useful when the muscle is stretched). Additionally, muscles can now have dynamics applied to them (no collisions, though), so they can react to gravity, motion and emulate their mass better.

These muscle objects can be anchored to other objects, joints or whatever you want so they can be stretched and squeezed the way you need them to.

Muscles deform the mesh, and change shape based on their length.

Adding muscles to your character is fairly straightforward:

That's it. From there, you can start creating your different muscle shapes for each state (or let the Muscle object calculate the volumes automatically) and adjust various settings if you want more control or dynamic behavior.

The Muscle objects themselves can be rendered, so make sure you hide them if you don't need to see them in your final render.

Tip:
You can precisely set the amount of influence muscles will have on your a mesh by adding each muscle object to a Weight tag applied to the mesh and painting their influence using the Weight Tool, much like how you would paint influences of joints.

This is a great way to refine the way your muscles affect your mesh.

Keep in mind that muscle objects need their own Weight tag, and not be mixed with joints or other objects, otherwise their influence will be normalized, instead of added on top of existing weights.