In the Edit > Preferences > Compositing we can set how many threads we want to use for the cooking and the Tile Size of each chunk of the tiles that will be processed. We can also set the Resolution Limit. If we do a mosaic of 1 K images we can exceed this limit and that can lead to issues.

The turn of the thumbnails of each cop node we can disable view > Show Node Previews in the menubar of the cop network view.

To set the Composit Project Settings and adjust things like resolution we go Edit > Compositing Settings This means that any nodes that we add that does not have an input will use this resolution (unles we override the resolution on the node). This means that we can work at a lower rez and set it higher when we export the images.

Nuke equivalent

Nuke nodes COPS equivalent
Read File
Write ROP File Outout
Grade Levels
Color Correct Color Correct
Shuffle Channel Copy
Premult / Unpremult Premultiply
Reformat Scale
Transform Transform (Xform)
Blur Blur
Merge Composite
Roto RotoShape
Dissolve Blend
Erode DilateErode
Keyer Luminance Lumakey
Chrome Keyer Chromakey

Houdini Illume | COPs with Mike Lyndon



Lets create a mosaic of an image sequence on disk:

  • In the Cops context create an Image Network (or use the default one)
  • Create a File node and set the file to the image sequence.
    • Note! if the images are not a sequence create a File node per image and create a Sequence node and plug in the file nodes.
  • Create an Mosaic node and plug in the file or sequence node we created earlier.
  • Create and append a Scale node and set the scale and filter to what you need.
  • Append a Rop File Output
A cop network creating a 4x4 number mosaic

How to

Add alpha channel to RGB

  • Create a Channelcopy node
  • Connect the file that has the rgb values to input 1
  • Connect the file that has a channel that you wish to use as alpha to input 2
  • Target > New Plane > A
    • Target the alpha
  • Source > Input2:C.r
    • Use the red channel of the second input as the alpha

Save unpremultiplied TGA & PNG

  • Rop File Output > Metadata tab > PNG/TGA Premultiplication