Deborah R. Fowler
Houdini Shading
Posted Jan 25 2025
Updated Jan 25 2025
Karma shaders - when working in Karma there are two options for Karma cpu (Karma xpu is not guarantee to respect principled shader)
- material X (mtlx) shader (USD file format)
- with mtlx comes two libraries of free shaders - the general
library and amd catalog
- principled shader (backward compatible to mantra - vex proper shading language)
- Material Palette presets
- principled shader (accessible from the Material Palette)
- classic shader (formerly called the mantra shader - accessible in the mat network by the tab menu)
Metal has the spec color of the metal, i.e. gold has a gold spec color. Plastic is white. Metal is highly reflective, little to no diffuse.
Reference, Reference, Reference - look at the material you are trying to mimic. Preferably a real object, or if not possible, a photograph.
History: In H16.5 and up there are two context for shaders and a convenience of creating them. These are the mat, shop and Material Palette. When you drag a pre-set shader onto the Palette, you are really creating a material node in the /mat context.
One super cool new feature in H16.5 is the ability to bevel edges in the shader, not the geometry. It is in both the principled and the classic shader under the Bump & Normals tab. (Similar functionality in Redshift as well).
Assigning shaders is covered in the section on Lights-RenderBasics.html
Let's also talk about textures and uvs in the section on Overview-UVs.html