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Showing posts with the label vopsop

Wear Shader

Just playing around with shaders - curvature and occlusion in SOPs to make a wear shader. In SOPs, made a little curvature vopsop. It is a vopsop to do curvature since the curvature SOP doesn't give a normalised result. Inside the vopsop, the neighbors of a point are looped through and the dot product of the direction to a neighbor and N is averaged for all neighbors. I shamelessly copied the idea from Dan: And some occlusion in SOPs, done in SOPs so that it only needs to be done once for all frames This is mashed a bit to get the result I want: Mult the two together: This is to represent where the surface is likely to get worn or chipped. I started with the default reflective shader and added a displacement shader that gets the wear attribute, mults it with noise, then that goes through a contrast function to give a sharp edge. That 'matte' is exported to the surface shader to control a few things in there like reflections, colour etc. hipnc file i...

Particle motion blur again and some point cloud lighting

Fixed a few things with the particle motion blur stuff. Mostly it was just to get rid of an issue where you could see the particles when rendered zipping back to 0,0,0 when they died. I changed the popnet so that the particles always die when the camera shutter is closed... I think this was because the surface shader is only evaluated once, so when a particle died (alpha set to 0) the surface shader wasn't used again so the alpha wasn't updated from the sim... The only problem with the fix is that you can't have any particles that live for less than the shutter time... This is useful for sparks (you can see some particles colliding in the image above), I also made a little point cloud shader that is also useful for sparks :D Houdini - particle deformation blur and point cloud lighting from Sam Hancock on Vimeo . The shader on the spheres and ground plane just loop through the particles and does diffuse, attenuation and shadows. A single frame took about 6.5 ...