How would I create this painterly effect?

TeapotPaintEffect.png

I need to be able to render each frame at least 3 times, then composite the images into the final frame. Each image will need to be rendered with a different world position offset value for the material.

It doesn’t look particularly painterly, but you could probably fake that look using meshes rather than a render effect. Use some kind of noise distortion on the main mesh and then add a second mesh that’s dark and translucent and add push it out a bit. Kind of similar to how people have done cell shading in the past–by making a copy of the mesh, pushing it out and then inverting it.