Passthrough - Arnold User Guide

Evaluate any shading network connected to the Eval[1-20] inputs. The Passthrough input is evaluated first and is passed as-is to the output. This shader is useful to force the evaluation of parallel shading networks that are not part of the beauty pass, whose resulting value you need to store in an AOV for example.

Bump

The bump allows for the assignment of a normal or bump map that affects the entire network of shaders it is connected to.