You find this function at the bottom of the Fitting Slider section. Use it as follows:
- Select a part of the mesh that shows a rough surface
- Click Smooth Weights one or a few times and watch how the selected vertices move around.
Hint: In this example you will need to not only modify the Belly Slider but also the Pelvis slider. And some vertices might not at all want to move into good places.
Important: This function does not touch the mesh itself. It only operates on the weights by trying to smooth the mesh surface very similar to what Blender’s vertex smooth tool does!