Creating attributes
An attribute is a number computed for every vertex or triangle — roughness, dip, curvature, intensity, height above a datum. Colouring a model by one is often the difference between a face that looks like uniform rock and one where bedding, fractures and weathering separate cleanly.
Attributes are computed from the object's context menu, and VRGS carries a large suite of them. They matter twice over: they make manual interpretation easier by enhancing what you are trying to see, and they are the input to automated methods such as classification and fracture detection, which have nothing to work with unless the information is in an attribute first.
Some tools work the other way round. Grow Planar Patches reads the mesh's own geometry and writes its results as attributes — a patch id, dip, azimuth and planarity for every exposed face — so colouring the model by Patch Colour afterwards is how you see what it found.
The Charts panel plots the active attribute's distribution, and dragging on the histogram filters what the 3D view shows. It is the quickest way to find out whether an attribute is telling you anything.
See Attributes for the full list and what each one measures.