Deborah R. Fowler

Houdini Cops

Posted Aug 8 2019

Houdini contains compositing operators (cops) which can be extremely useful for many purposes, for example:

testing layers
creating/animating textures

There exist the basic operators you would expect in a compositor but you can also access the information.
For example, if you create a noise pattern and want to apply it to a surface or a project map in a light you can create it in the img context (or create a COP2 Network container at the obj level).

To reference the pattern you specify the path prefaced with op:

This is demo'd in the sample file simpleExampleCops.hipnc (H17.5)
This path could be referenced either in the shader, or in the material node as a material override.

Operations such as over, merge, etc. are available. There are not cop wrangles, but you can use snippets inside of vex - thanks for the tip from Matt Estella's page on cops.

There is also a Houdini Illume webinar by Mike Lyndon on the topic of COPs.

Potentially, you can build procedural textures. An example using just a simple toggle to tile either one or two mandril images is given here.

Houdini Resources

Deborah R. Fowler

Houdini Cops