Houdini Attribute Scrambler SOP v3.0 HDA (Python 3 compatible)

Attribute blending similar to Photoshop layer blending modes.

Valid input attributes: point/prim float and vector (3 floats, which includes color).

It helps keep node graphs cleaner and it's fun to use. (Disclaimer: 'fun' is subjective:) Reduces the need for common, repetitive tasks, like binding and exporting attributes in attribute VOPs or typing in wrangles for things like lerp or any of the operations below:

Supported operations:

1. Copy (v3)
2. Add
3. Subtract
4. Multiply
5. Divide
6. Minimum
7. Maximum
8. Average
9. Screen
10. Overlay
11. Exclusion
12. Linear Interpolation
13. Pin Light
14. Difference
    

A demo of v2 which lacks a few options and features but works in much the same way otherwise:

Changes in v3.0:

1. Entirely re-written
2. Advanced VEX (scroll to the bottom for more info)
3. 'Copy' operation - just overwrite all previous operations with this attrib (useful for then/now comparisons while dialing in your final numbers)
4. Python 2 & 3 compatible
5. Vector (3flt) support (that includes color)
6. Creates the (input) attribute if it doesn't exist (and indicates that to you)
7. Not compatible with v1 and v2 (but both are included inside)
8. Parameter interface
9. Dynamic drop-down menus will list compatible attributes only.
   

Inside the HDA: Attribute VOP and Attribute Wrangler are essentially identical. The former contains a single snippet of code and is independent of external 'include' files. The latter is there for debugging convenience but requires an #include directive for haki.h (haki.h needs to be copied to $HOME/houdiniX.X/vex/include)

If you want to study it on your own, you've got:

• Declaring and using a struct in VEX via outer code or include directive
• Looping over a multi-parm in VEX
• Generating menu items using Python Menu Scripts with conditional formatting
• Dynamic "Hide When" through custom functions in the HDA PythonModule (advanced)
• Using the HDA "Descriptive Parm" with a Python script for dynamic hints

(If you take that road above, remember to "Show Invisible Parameters" first.)