I've improved a few parts of the script.  The marker has been changed to improve visibility and scale in Poser and has had its geometry centered and its origin set to [0.0,0.0,0.0].  This helps with more accurate positioning for the final path. 

I've also done my best to correct the spline handling when creating a closed path.  The spline now carries through all the way back to the start, but the join where the end meets the start is not quite 100% perfect.

Finally, I added the option to create an open tube without caps.  One might want to model something with tubes in Poser, working with the scene, then weld together open ends of various tubes in another application to create a final geometry.  Or create a tunnel or something.

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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.