Face Contours

Back again. This started as something else, but ended up with finding contours. I calculate the difference between a sphere and a face, and in uv-space get the curl, which is then projected back onto the mesh.


Max velocity volume blending

Velocity volume blending has always had a glaring omission in my opinion. Add mode gets out of hand, Blended Average values are hard to nail down, what I want is to pick the greater velocity from the existing vel and my new source vel. I’m sure most users think that’s what Maximum mode is, but it is not! In fact it picks the larger numeric value for each component – so if you have a volume of {0,0,0} and you try to blend in some {-2,0,-2}, you still end up with a volume of all zeros. This is easy to confirm with the attached scene by bypassing the added switch node.


The attached scene has an additional Field VOP that overrides the default Maximum behaviour with what I think is the more logical operation – the longer velocity vector is picked for each voxel.



Multi-scale Turing Patterns

This really is an old (2011) project of mine – I just recently found the hip file, presumed to be lost. This was implemented according to this adaptation of McCabe‘s original pattern. It was built earlier with the aid of the ancient proto_install feedback SOP, but here modernized to use Solver SOP. I just solve a cubical pattern and cut out a pig-sized shape out of it, it would be a nice project for another evening to make the process more shape-aware.



Better Normal Blending

Houdini 16 comes with new operators for normal map manipulation. The Normal Combine COP blends the incoming normals by just taking the average, and that is far from an optimal way to blend two normals. Stephen Hill has a very good web page on normal blending, and I have used his Reoriented Normal Mapping with great success in the past. The idea is, that instead of blending the normals you rotate one normal according to the orientation of the other normal. The end result is a much more natural blend. Here is a hip file with an RNM replacement for Normal Combine COP, and it also has a blend amount slider.