I write a PoserPython script that starts like this:

mats = poser.Scene().WacroMaterials()
if mats:
    for mat in mats:
        doStuff(mat)

The script is on my desktop.

I assign my script to one of the ten wacro buttons(alt-click a wacro button to remove the existing assigned wacro, then click the button (now labelled '...') to select and assign my script)

If I now run my script by clicking the wacro button it runs for the current material only, as expected. If I run my script by shift-clicking the wacro button it runs for the all materials of the current object, as expected.

If I run my script via File > Run Python Script it sometimes runs for just the current material, but sometimes for all materials of the current object. It seems to depend on how I last ran a wacro from one of the ten buttons.

It appears as if running a wacro from one of the ten buttons sets/clears a global flag that indicates current/all materials, and it seems that WacroMaterials() builds a list of mats for the current object based on the current setting of this flag.

Does anybody have any insight into this ?

you might be able to add a statement like print Len(mats) to see how many materials are being selected.

Thanks - that's similar to the approach I've ended up using. I've already had feedback on two other forums which helped clear up my understanding on this. I'm not going to duplicate what I said on them, so I'll just link* to them:

https://community.hivewire3d.com/threads/poserpython-wacros-and-scripts-wacromaterials.904</https:>

https://forum.smithmicro.com/topic/179/poserpython-wacros-and-scripts-wacromaterials/7

(*Links legitimately included on this basis. )