Vertex Weight modifiers to adjust softbody/cloth simulation?

Question

I want to use vertex weight mix/edit modifiers to adjust weights of a complex mesh for a softbody/cloth simulation. I'm able to use the modifiers to successfully adjust the vertex weights, but it seems like the only way to get them in the simulation is to apply them.

Apparently cloth and soft body simulations do not allow vertex weight modifiers to precede them in the modifier stack. I get an warning message saying Cannot move above a modifier requiring original data. This means that the changes to the weights are not seen by the simulation, since it "requires original data" and only looks at the original vertex groups.

Normally, I'd weight paint by hand, but I'm using internal structure for these simulations, and there is no way to paint vertices inside of a mesh. Is there any way to be able to use these modifier stacks without having to apply them every time I change something?

Answer 1

Soft body does not allow modifiers above the soft body. But cloth physics (which is a form of soft body physics) does:

If you're having trouble painting internal geometry (that has faces), you can do so by switching to vertex masking mode in weight paint mode, tabbing to edit mode to hide vertices, and then tabbing back to weight paint mode. The faces that are hidden in edit mode will remain hidden in weight paint mode.

You might still have trouble weight painting vertices that are not part of faces, and those kinds of vertices are relatively common when working with physics. However, you can still use the properties/vertex groups panel to assign or remove these vertices, and you can still use weight paint operations like "normalize all" on these vertices; you can also use a data transfer modifier to copy weights painted on some other mesh, to these unfaced vertices. In the worst case scenario, where you absolutely need to paint them, you can make faces for these vertices, paint, then delete those faces.