Search found 58 matches

by ndl
Sun Feb 17, 2019 4:40 am
Forum: Stella Feature Requests
Topic: Curved Shapes
Replies: 1
Views: 40125

Curved Shapes

It would be great if there was a option to smooth out certain edges in order to create curved shapes. The two adjacent faces could be considered one curved surface. In 4D also you could have curved cells. The inner geometry would still just be an approximation but the view could look curved and the ...
by ndl
Fri Feb 08, 2019 4:05 am
Forum: Stella Forum
Topic: Non-Uniform 4D
Replies: 17
Views: 57852

Re: Non-Uniform 4D

I figured out the problem: I was using the wrong formula to calculate the vertices so the ones I had were creating coplanar faces so that's probably why it was crashing. Once I fixed the formula it worked no problems.
by ndl
Thu Feb 07, 2019 2:57 pm
Forum: Stella Forum
Topic: Non-Uniform 4D
Replies: 17
Views: 57852

Re: Non-Uniform 4D

I made the following .off file but when I open it in stella4d and ask it to make convex hull the program crashes. Do you know what could be the problem?

cylindrical crind.off
by ndl
Mon Jan 21, 2019 3:39 am
Forum: Stella Forum
Topic: Non-Uniform 4D
Replies: 17
Views: 57852

Re: Non-Uniform 4D

Yes, convex hull is what I need and it works just fine. Thanks again
by ndl
Sun Jan 20, 2019 3:50 am
Forum: Stella Forum
Topic: Non-Uniform 4D
Replies: 17
Views: 57852

Re: Non-Uniform 4D

It got confused when I listed cells, but I did a listing of just the vertices and it created the 4D convex hull for me! Thanks for your help.
by ndl
Thu Jan 17, 2019 4:17 am
Forum: Stella Forum
Topic: Non-Uniform 4D
Replies: 17
Views: 57852

Re: Non-Uniform 4D

I'm trying to work with .off files to create 4D non-uniforms, but it's way too tedious to try to figure out all the faces and cells that would connect the vertices. I found this program called qhull (www.qhull.org) that will calculate the convex hull and create an .off file from input vertices, but ...
by ndl
Tue Jan 01, 2019 4:24 am
Forum: Stella Forum
Topic: Non-Uniform 4D
Replies: 17
Views: 57852

Re: Non-Uniform 4D

What about an ability to cut off pieces of uniform polyhedra? That would give rise to lots of interesting non-uniforms. Maybe create it by choosing a cross section to cut it at (this could really be a great feature for 3D also!).
by ndl
Mon Dec 31, 2018 4:45 am
Forum: Stella Forum
Topic: Non-Uniform 4D
Replies: 17
Views: 57852

Non-Uniform 4D

I just got Stella4D and I'm trying to play around with it. It seems you covered pretty extensively 4D uniforms, but I had trouble trying to create non-uniforms. I wanted to make an Icosahedral pyramid, for example, so I tried using a J2 pentagonal pyramid as vertex figure to create it, but it only ...
by ndl
Thu Dec 20, 2018 5:07 am
Forum: Stella Feature Requests
Topic: Augmenting with polyhedra
Replies: 3
Views: 46556

Re: Augmenting with polyhedra

That's good to know. Thanks again
by ndl
Thu Dec 20, 2018 4:13 am
Forum: Stella Feature Requests
Topic: Augmenting with polyhedra
Replies: 3
Views: 46556

Re: Augmenting with polyhedra

Never mind, it seems that feature is already available and I overlooked it.
by ndl
Thu Dec 20, 2018 3:39 am
Forum: Stella Feature Requests
Topic: Augmenting with polyhedra
Replies: 3
Views: 46556

Augmenting with polyhedra

Could there be a way to choose which matching face of existing polyhedron is used for augmentations? Often I find I want to use a different one than which is automatically chosen.
Thanks
by ndl
Thu Dec 20, 2018 2:54 am
Forum: Polyhedra
Topic: New Torus
Replies: 9
Views: 77452

Re: New Torus

And an alternate version with antiprism and cupola replacing rotunda:
J76 Genus 6 alt.JPG
J76 Genus 6 alt.JPG (57.53 KiB) Viewed 77173 times
by ndl
Thu Dec 20, 2018 2:35 am
Forum: Polyhedra
Topic: New Torus
Replies: 9
Views: 77452

Re: New Torus

Even better, I got one with a genus of 6 and retaining the original symmetry of J76 by cutting through with a Dodecahedron and 5 J11s
J76 Genus 6.JPG
J76 Genus 6.JPG (46 KiB) Viewed 77174 times
Still quasi-convex!
by ndl
Wed Dec 19, 2018 7:20 pm
Forum: Polyhedra
Topic: New Torus
Replies: 9
Views: 77452

Re: New Torus

So I created a new toroid that has Stewart's quasi-convex property that doesn't seem to be mentioned in his book (I only have first edition, though):
J76 Torus.JPG
J76 Torus.JPG (44.46 KiB) Viewed 77176 times
This is J76 with a rotunda and two icosahedra removed for a genus of 2.
by ndl
Wed Dec 19, 2018 7:12 pm
Forum: Polyhedra
Topic: New Torus
Replies: 9
Views: 77452

Re: New Torus

I found another interesting one yesterday:
J32 Torus.JPG
J32 Torus.JPG (30.31 KiB) Viewed 77179 times
This is a J91+J63 Tunnel through a J32 (Pentagonal Orthocupolarontunda)

I realized then that J32 had a cross section of 2 of those irregular hexagons that Stewart talked about inside a Rhombicosidodecahedron.