Rda is the arithmetic mean of absolute gradient for a surface roughness profile. It is a description of slopes along a surface, and it tells us how a surface might appear or how light may reflect off of it. The Da parameter describes the slopes on the surface. While Rda is calculated from the roughness profile, the calculation can also be performed on the waviness profile (Wda) or primary profile (Pda).
View all the surface texture parameters in our Texture Parameter Video library.