Update the 4D libraries to reorganize and add new uniform polychora, plus demonstrations on polychora symmetries

[Mulliganaceous]

Dear Robert Webb,

I enjoyed using Stella4D, although unfortunately, selection of elements seemed to be glitchy compared to the demo version.
I am still awaiting for the reorganization of the 4D library to support and reorganize the uniform polychora, plus samples of polychora for each polychoral symmetry.

• http://www.polytope.net/hedrondude/polychora.htm

• http://www.polytope.net/hedrondude/decaic.htm

• http://www.polytope.net/hedrondude/sym4.htm

[robertw]

Hi, I will try to get a new version of Stella out this year, hopefully sooner rather than later. It's been in limbo for a while, for various reasons. Partly because I've worked on other things (like music), but I have worked on Stella too.

The last release was over 10 years ago now! It was built using tools from last century which no longer even work on Windows 10, so I can't do a minor release (next release will be the major 6.0 release). But I now have it built and working with the latest tools. I still have work to do though before it's ready for release, and no ETA.

Onto your questions.

• Selection issues: only a few people have experienced this. Discussion is here: https://www.software3d.com/Forums/viewtopic.php?p=2547 Summary: I think it's been fixed at my end, and Ulrich posted a work-around. Did you try that? Does it work?
• Reorganise the 4D uniforms: I presume you're just referring to Category 26 which was accidentally placed under Category 24? It will be fixed in next version. For now you can simply move that folder yourself. You'll find it where you installed Stella4D, probably "C:\Program Files (x86)\Stella4D". Discussion was here: https://www.software3d.com/Forums/viewtopic.php?p=2536
• New 4D uniforms: yep obviously new discoveries since the last version of Stella aren't in Stella yet. Hopefully they'll be in the next version. Someone did send me a bunch of 3D vertex figures so Stella4D could create the new uniforms, but not sure if it was a complete list. I'll at least need the official number, abbreviation, and category number for each. What's the total up to now?
• "Samples of polychora for each polychoral symmetry": not sure what you mean here. Stella doesn't provide samples of each symmetry in 3D either. But you did ask before for Stella to show the name of the 4D symmetry group. I still can't do that yet, and it may be too much work to do completely and reliably, but I need to look into it.

[H A M]

Obviously when new discoveries are made the 4D library gets outdated.
Use this collection of OFF files of polychora instead which is updated: https://drive.google.com/drive/folders/ ... aXpOSLQOZi
It even includes caco which shares the same vertex figure as srohp! Those OFF files are made using Miratope which can facet polychora: https://github.com/galoomba1/miratope-rs

[robertw]

I've now got every known uniform polyhedron added to Stella4D's library for the next release, including all the new ones, all the way up to 2188! And all the vertex figures work now (some of the new ones had issues initially).

The folder you linked to is missing a lot still. Cat 29 only has 2 out of 177, and the new Cat 30 only has 13 out of 333.

Jonathan Bowers sent me .stel files for vertex figures for the 5 new cores in Cat 30, along with a few extras. I generated the rest based on his page describing them.

Caco (scaliform not uniform) is one I still have problems with. Will look at that sometime.

[H A M]

And many compounds can't be generated from a verf so they have to provide the whole polychoron (in OFF so it can be opened in other programs like Miratope) instead.
Correction: There are 2191 known uniform polychora now.

[robertw]

Sorry yes 2191. I was forgetting the highest number wasn't in Cat 30. But don't worry, I've got them too.

Currently Stella4D only has 4D compounds that can be generated from their vertex figures in the library, although yes you can bring them in via OFF if one is created outside.