Boy, I had that last posted script all wrong.  Hmm.  I think this can be made to work, so I'm working on a complete re-write of the idea, even though it's a bit of a digression....

Okay, I read the new .pyd readme, and let's see if I now understand, or whether I'm confused.  Can I generalize and say that any time I'm going to use one of the math operators on a vector, I should be prepared to be handling a reference, so I should use Clone() unless I definitely want to change the source vector?

tempvec = listvec[x]
tempvec += othervec # will alter listvec[x]
newvec = tempvec + othervec # will not alter listvec[x]
newvec = listvec[x] + othervec # will not alter listvec[x]

tempvec = listvec[x].Clone()
tempvec += othervec # will not alter listvec[x]

Is that correct?  :hopeful:

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Cage can be an opinionated jerk who posts without thinking.  He apologizes for this.  He's honestly not trying to be a turkeyhead.

Cage had some freebies, compatible with Poser 11 and below.  His Python scripts were saved at archive.org, along with the rest of the Morphography site, where they were hosted.