QUICK REFERENCE #002: Face Normals Scatter In Houdini

Tutorial / 06 September 2020

This is my first week of really giving Houdini an actual go! I wanted to scatter along face normals (specifically THE face normal) and there didn't seem to be an 'out of the box' way to do this so here's a node that puts a point in the center of a face and carries the normal of the primitive over for all your face scattering needs:

A Primitive Wrangle SOP containing this code junk


Network in context, just slap that bad boy onto your scatter surface then pipe into a copy SOP


Wowcool


I wanted to scatter some stuff on the face normals of a sphere (akin to a scatter from Maya from MASH or spPaint, maybe my mistake of trying to make Houdini act like Maya). Ran into my first real problem that highlight some of the things I'm loving and hating about Houdini at the same time a few days in:

  1. 'Face normals' as they are in Maya don't actually exist in 3D (vertex normals do!) so where Maya fabricates a workaround, Houdini presents the issue as a fundamental problem for you to solve rather than pretending the problem doesn't exist
  2. There are at least 18 different ways of doing the exact same thing in Houdini
  3. If a node doesn't exist, you just have to assume the mantle of creating the node
  4. How the fuck do you find any of this out

Alot of the solutions I found for this either seemed obsolete or inelegant so in the end after many hours of not even knowing what to Google, I stumbled my way onto this super basic blob of code. Hope it helps?!?