I, Houdini

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 sn...

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)

More paper stuff! Updated it, now using a SOP solver to modify the velocity. The last one was a field force which wasn't great. Also this one projects the velocity vector onto the surface rather than just applying an opposing force like I was doing before. The velocity ends up perpendicular to the normal, with this: cross( nV, cross( nV, nN ) ). That is mixed with the original velocity to get more or less of the effect ... In the linked .hip file there is a VIS_PROJECTION null that you can view to see what I mean... Houdini - New cloth paper thingy! from Sam Hancock on Vimeo . You can get the hip file from here (H11)

Haven't posted in a long time, easing back into it with something I was playing with about a year ago ... it uses the same wind resistance stuff that I was using earlier. Going to update it in the next few days with a much better way of doing it with a SOP solver! Houdini - Cloth paper thingy from Sam Hancock on Vimeo . Each piece of cloth is simmed individually, a wedge ROP is used to write out a geo sequence for each piece and they are brought back in using a file SOP and a copy SOP. The pieces don't collide .. but it doesn't matter so much with these .....

This is why Houdini is awesome, one node ignored and changed the bias on the ray SOP, and self shadowing just works :D It probably needs a wind location specified so I can timeshift the occluding objects depending on the distance from the wind 'emitter'. meh. hipnc is here

More cloth! Got some wind shadowing working using the same technique as the wind resistance thing, just with a ray SOP to block the wind. Currently the wind gets blocked by any other objects in the dopnet. Might add self shadowing next! This is with wind resistance from earlier, just adds some damping. hipnc is here.

Normally a cloth like this: would just fall and retain this exact shape... I put together a little force using the field force DOP and a little sopnet to get a basic simulation of wind resistance as it falls. The force is applied along the normal, opposing the velocity. It is also scaled by velocity. Here is an example: Blue is the point normal, green is the velocity and red is the force to be applied. This is far from correct but it works alright in practice. This cloth is 2m x 1m and low density (less than a kg total I think) hipnc file is here!

I saw this post over at odforce and have been playing with growing objects in a dynamic way ... It is basically just points scattered in the volume of an object, then a SOP solver is used to increase a points pscale if it is colliding with another point. Metaballs are copied onto the points, converted to polys, then cookied with the original geo (not in the video above though...) This is the source geo and with the scattered points: Some attributes are added for the sim: The pscale attribute is set to 0 except for one which is set to maxSize to start the sim going. Roughness starts at 1 and decays when a point has stopped growing, this later is fed into the shader to increase the cone angle on the reflections and refractions... These points get loaded into a DOP network and then into this SOP solver: The pointCloudSop is a little VEX script that tests for collisions between points: #pragma hint filename oppath #pragma hint pscale hidden #pragma hint maxSize hidde...