FUSION · NODE REFERENCE
Channel Booleans
Channel math and copying
Combines, copies and mathematically remaps RGBA channels between foreground and background images.
Channel Booleans
Overview
What Channel Booleans does
Channel Booleans performs mathematical and logical operations on image channels. The Background input supplies the base channels being modified, while the Foreground input can provide alternate source channels.
Operation Type defines the math, and the To Red/Green/Blue/Alpha mappings define which source channel participates in each output channel. This makes the node useful for replacing alpha without touching RGB, building technical mattes and repairing channel layouts.
Copy is the safest starting point when the task is simple channel routing. Add, Subtract, Multiply, Maximum, Minimum and logical operations should be used deliberately because gray values are continuous and can produce results very different from a visual Merge.
Auxiliary channels such as depth, normals, vectors, position or IDs only exist when the source actually carries those passes. Enabling Aux does not create missing data.
When to use it
Copy alpha from one image to another
Build a matte from channel data
Multiply or add technical passes
Combine RGB from one source with alpha from another
Create difference or minimum/maximum channel operations
Repair channel layouts in imported assets