The Curvature VOP allows you to add wear and tear to geometry easily, and procedurally. Perfect for adding dents, scratches and dirt on certain parts of the model. There, the Side FX teams shows a demonstration that uses Curvature in Houdini 15.5 for adding grunge to a model.
The Curvature VOP uses your geometry to find the highlights of the surface, as well as the creases
Curvature reads the geometry and search for the details of the model, such as highlights and creases. You can then use this to add procedural dirt and grunge to a model, using the same procedural noise to generate an accompanying displacement. This can be done by creating a base principle shader and then mixing a brushed metal shader in, using the output from the Curvature VOP as a mask.