How to Modify Houdini’s Principled Shader to Detect Alphas

CG Generalist and FX Artist Tim van Helsdingen posts a look into ways that you can add alpha maps To the Principled Shader in Side FX Houdini. If you are not familiar, the Principled shader is a SHOP shader that is a physically plausible monolithic shader in Houdini.

As a type of “catch all” shader that is meant to be an artist-friendly shader that can model any number of materials. It does this with relatively few parameters. This is one of the reasons that Tim thought it strange that the new Principled shader didn’t have default settings for treating alpha’s.

Tim walks through creating a system that allows you to either use an image alpha, or an alternate alpha map.

As a side note, you should check out Tim’s effort into larger scale fluid simulation in Houdini where the result is a realistic looking mountain river. Pretty great!