Groups of Operators
* SOP = Surface OP (3D = geometry modeling)
* POP = Particle OP
* SHOP = Shader OP
* COP = Composite OP (2D = compositing, image processing)
* CHOP = Channel OP (1D = channels, mocap, audio, logic)
* VOP = Vex OP (VEX = Vector EX-pression language, shaders, custom operators of any type)
* ROP = Render OP (outputs for all data types)
* DOP = Dynamics OP (simulations, dynamics solvers)