Houdini 19.5 Compositing

Generate mattes based on image colors (keying)

Houdini includes several operators to let you isolate, select, and/or remove areas of color.

To do this… Use this operator
Remove color and produce alpha mattes.


Copy the luminance to the alpha channel.

Luma Matte

Replace one color with another.

Color Replace

Mask luminance in/outside a certain range.



The Chromakey, Color Replace, and Lumakey operators have a supersample parameter, which gives anti-aliased edges at sharp color transitions. A supersample value of 3 is usually sufficient. Higher values will really slow down the operation. If you don’t want antialiased edges, set supersampling to 1.

To select areas of color interactively (like the Magic Wand in Photoshop), make the node active (select the node in the network editor and press Enter in the viewer) and use the following keys:




Camera effects


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