Skip to main content


Showing posts from July, 2011

Deforming RBDs again!

In this one I have changed to adding up all of the impacts rather than the mixing that was going on with the attribute transfer in the last one. It is just a vopsop which loops through the impact points and adds up the deformation.

One problem I was having was when I deformed the object, the centre of mass was in the wrong spot. I couldn't figure out a good way to modify that in DOPs... so i ended up moving it in the sop solver, to get it centred again. Another problem was that the object wouldn't be in contact with the ground after it was deformed, so it would end up in mid air with no velocity.. so I added a move attribute in the sop solver, then in DOPs I used a modify data node to move the rbds. The problem with this is that for one step of the sim it would be hanging out in mid air, and then snap to the ground. I ended up just adding the move to P in SOPs after the simulation.... not great because the object isn't solved at that position. At least it doesn't snap …

Deforming RBDs

Simple setup that uses a SOP solver and deforms the geo at points of impact. The impact data is already available in the SOP solver, the normal is the impact direction and there is a pscale attribute for the magnitude of the impact.

In this setup I just used attributeTransfer to get the impact data onto the mesh, then a vopsop to deform the mesh. There is a minimum impact so that resting objects don't get deformed. Also I divide the impact magnitude by the mass... the heavy box was denting itself from just resting there.

Houdini - Impact deformation for RBDs from Sam Hancock on Vimeo.
Might be better to have an additive effect for getting the impact data onto the mesh, rather than the averaging that goes on with the attribute transfer ... might try it later.

Also going to try getting some volume preservation going on!
.hip is here! (H11)