Okay.  It's getting there.  :laugh:

I've made options to trim a path to the submitted chain length by number of links, extend the chain to the end of the path, or scale the path to the submitted chain length.  All working nicely.  (And all thanks to the magic of odf's revelation about matric construction from a set of orthogonal vectors.  :woot:)

The main problem now is that the links can slip out of their proper places at sharp transition points.  You can see a bit of that on the linear chain on the left, in the attached image.  I'm going to see what I can do to correct that.

Aside from that, I just need to finish the Tkinter GUI for P7 and below, and the static-chain-prop-along-a-path script will be ready.

A script to pose a chain figure from the path is more daunting, at least to me.  :scared:  There would seem to be no avoiding angle conversions there, as Poser parameter dials will only accept euler angles as input.  (A pity there's no option to set rotations using quaternions, as in Blender.  Poser supposedly uses quats internally, but there's no Python access, if that's the case.)

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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.