POSE SPACE DEFORMATION
Create a Pose Morph tag for the elbow control PSD morphs can help you get the correct skin shape for certain poses, such as fixing creases or even adding muscle or fat definition. Starting off with a rigged character, you first need to add a Pose Morph tag to any rig control. We’re going to use the right elbow control here.
Add in a new pose Open the elbow control’s Pose Morph tag. Now switch over to Edit mode and then click on the Add Pose button. By doing this, Cinema 4D will add in a new pose that you will then be able to use for creating the corrective shape. It’s called Pose.0 by default, but you’ll probably want to rename that when you start creating more of these poses.
Sculpt the corrective shape Now that the skin’s current deformation is being considered, you can make use of any of the usual tools that you’d call upon for fixing the skin, like the Brush tool, for example. Here, we can now get to work smoothing out the crease and maybe add in a bit of a bicep bulge for a flexed pose. And that’s pretty much all that you have to do here!
Pose the arm where you need the corrective shape Rotate the elbow control so that the arm is in a pose where you need a corrective shape. This is usually at a point where joints are bending and creating unattractive bulges or creases. It’s hard to fix this using only joint weighting, which is where these shapes can help out.
Switch to Correctional PSD mode If you leave the Mixing in Relative mode and then try to edit the skin’s points, it doesn’t work because it’s not taking the skin’s current deformation into account. All you need to do is switch the Mixing mode to Correctional PSD. The Post Deformers option automatically turns on and PSD Settings show up below.
Edna Kruger teaches you how to create corrective shapes for skin based on a video by bret bays on cineversity.com
Rotate the elbow control Switch back to Animate mode in the Pose Morph tag, and then watch the corrective shape automatically fire as you rotate the elbow control in and out of this pose. And no Xpresso is required for this to work, since this is controlled with the Auto Weighting option on the new PSD tab in the Pose Morph tag. It is so easy to do.