Curvature VOP in Houdini
This video demonstrates the Curvature VOP in Houdini. The Curvature VOP uses your geometry to find the highlights of the surface, as well as the creases, which you can explicitly control. We will use it to add procedural grunge on a gear object and use the same procedural noise driven by the Curvature VOP to generate accompanying displacement on the geometry as well. We do so by creating a (base) Principled Shader, and then layer-mixing a Brushed Metal Shader and using the Curvature as a mask to blend the two together.