Maya Pymel _ assigning shadingGroups

Coding
1

Hi there,

heres a thing I cant understand in Maya pymel;

Im using this very basic cmd to assign a shader to shapes in a loop:

pm.sets( myShader ,edit=1, forceElement=myObj)

but it returns:

Warning: None of the items can be added to the set

while if I use the same cmd on the Transforms it will work…
which is weird - since to be able to get a shadingGroup from a mesh, you need to select the shape and not the Transform…

shader = pm.listConnections(myShape ,type = ‘shadingEngine’) – of course theres a connection between shape and sg but its the overall philosophy that puzzles me.

Does anybody knows about this issue and can explain it, plz?

2

Sets command
The sets command’s forceElement parameter should be the actual set and the first argument should be the objects that get added to the set. :slight_smile:

So something like this:

pm.sets( objects,edit=1, forceElement=shading_engine)

Also see:
http://help.autodesk.com/cloudhelp/2015/ENU/Maya-Tech-Docs/CommandsPython/index.html

Maybe that’s where something goes wrong?

Maybe listSets over listConnections?
listSets
Besides that (and not many people seem to know this) getting the shadingEngine from a mesh can be done with the listSets command. :slight_smile:
I’ve done some tests and listSets definitely beats listConnections on performance tests; though I’ve seen it behave inconsistently when working with namespaces.
Just so you know you can also have a look at that command, but do keep in mind that it might behave differently.

listConnections
Note that a connection might (theoretically) exist between a shape and a shadingEngine for other reasons than it being assigned the shader. Most of the time it will be fine though, like 99.99%. :smiley: