I am working on a 3D simulation asset for making footprints onto surfaces, for a client, in Blender.
I’m rather new to the simulation world, and although it seemed simple at first, the more I explore the more complex it gets. The client needs it for a handful of shots where two dinos are walking on a beach, so the deformation must look like that of sand in the end, and unfortunately I can’t rely on more sophisticated physics techniques such as MPM (material point method) because Blender doesn’t have them. Simply moving vertices like I’m doing is also a simpler approximation, more adequate to solve this simple problem unless you’re Industrial Light and Magic.

So at each simulation step I need to raycast against the dino geometry to make the footprints per se (simple), then I need to track the amount of material that is being displaced by the dino feet and move the surrounding material up by the same amount, to create that bulge (less simple). It’s relatively incompressible material is why. The animation being imperfect (talons accidentally penetrating the ground inbetween steps) means I also have to detect and discard those interactions.

I have trouble letting go of a problem once I’ve started working on it so here I am, laying in my bed, thinking about the next steps…