Search found 569 matches

by robertw
Thu Dec 02, 2021 2:44 pm
Forum: Stella Forum
Topic: Can you export a net as a .dxf file?
Replies: 2
Views: 51

Re: Can you export a net as a .dxf file?

No you can't export nets as DXF I'm afraid. But if you export a DXF with the Stellation view selected, it will export the externally visible parts only, which is probably what you want since you said you want to see the intersections.
by robertw
Fri Nov 12, 2021 4:51 am
Forum: Stella Forum
Topic: 4D
Replies: 1
Views: 139

4D

Someone asked me to explain 4D, so I thought it would be better to do it here in a post for all to see. We only have 3 spatial dimensions in our world, but mathematically one can work with any number. There's no inherent restriction to 3 dimensions, it's just the way our particular universe appears ...
by robertw
Tue Oct 19, 2021 1:26 pm
Forum: Polyhedra
Topic: What is this Polyhedra called.
Replies: 7
Views: 574

Re: What is this Polyhedra called.

Ulrich wrote:
Tue Oct 19, 2021 9:13 am
I tried to make something like that from 6 „pentagrammic rings“
Nice job
by robertw
Mon Oct 18, 2021 1:42 pm
Forum: Polyhedra
Topic: What is this Polyhedra called.
Replies: 7
Views: 574

Re: What is this Polyhedra called.

That's OK. I forgot to mention another model I made that probably looks even more like it. A stellation of the small stellated truncated dodecahedron.
https://www.software3d.com/StelSSTD.php
Image
by robertw
Mon Oct 18, 2021 1:34 am
Forum: Polyhedra
Topic: What is this Polyhedra called.
Replies: 7
Views: 574

Re: What is this Polyhedra called.

Hello, I found this toy and am curious what geometric form it is called. It is essentially 6 5-pointed stars interwoven. At first I thought it was a dodecahedron, but after closer inspection it seems to have some triangle shapes in it as well. Yeah I've seen these before. It's not really a polyhedr...
by robertw
Wed Sep 29, 2021 3:51 pm
Forum: Polyhedra
Topic: Two new noble polyhedra - a new source of convex hulls to search from?
Replies: 27
Views: 8038

Re: Two new noble polyhedra - a new source of convex hulls to search from?

Robert, does this mean that we will never be able to solve the noble polyhedra problem with the help of Stella4D? No, but it might be a while. I'll try to get it to compile for 64-bit again sometime, but I seem to remember it wasn't straight forward. Another thing I should do is add the ability to ...
by robertw
Tue Sep 28, 2021 1:52 pm
Forum: Polyhedra
Topic: Two new noble polyhedra - a new source of convex hulls to search from?
Replies: 27
Views: 8038

Re: Two new noble polyhedra - a new source of convex hulls to search from?

Ulrich wrote:
Mon Jun 07, 2021 10:22 am
I gave my computer another 16-GB memory ... Stella crashes as before...
Stella is still a 32-bit program, so it has a limit of 3 GB of memory. So I'm afraid adding won't memory won't make a difference.
by robertw
Fri Jul 16, 2021 1:29 pm
Forum: Stella Feature Requests
Topic: Fixed Polychoron Slicing
Replies: 3
Views: 862

Re: Fixed Polychoron Slicing

OK thanks, I've made a note to look into it, but might be a while
by robertw
Thu Jul 15, 2021 3:20 am
Forum: Stella Feature Requests
Topic: Fixed Polychoron Slicing
Replies: 3
Views: 862

Re: Fixed Polychoron Slicing

Can you provide some specific examples? The simpler the better. Do the faces of the slice visit vertices more than once maybe? That makes it ambiguous as to how to traverse them, so if faces of the same type get traversed in different ways, then overall it may lead to no symmetry. But I'm just guess...
by robertw
Mon May 03, 2021 3:03 pm
Forum: Stella Forum
Topic: Vertex issue -1.#IND
Replies: 2
Views: 1405

Re: Vertex issue -1.#IND

Hard to say without seeing the OFF file, but looks like a disivion by zero maybe. Not sure what would cause that, but maybe there's a degenerate face? Eg a face where all the points are the same, or along a line?
by robertw
Fri Apr 16, 2021 5:30 am
Forum: Stella Forum
Topic: Selecting issue
Replies: 7
Views: 2173

Re: Selecting issue

I just tried again here, but can't reproduce it. It's very hard to track down at my end unless I have a way to replicate it. Also means it's probably related to the device you're on. So I'm afraid there's probably not much I can do. I don't suppose it makes a difference which Shift key you use? Gras...
by robertw
Thu Apr 15, 2021 9:13 am
Forum: Stella Forum
Topic: Calculating duals
Replies: 4
Views: 1357

Re: Calculating duals

Hmm, maybe, although that would still be wrong in the simple case of J2. It would lead to a centre outside the polyhedron, and not the point that would lead to a self-dual, so it might be kind of odd. This centre is also used as the centre of rotation, by the way, so the J2 would look odd rotating a...
by robertw
Wed Apr 14, 2021 4:03 am
Forum: Stella Forum
Topic: Calculating duals
Replies: 4
Views: 1357

Re: Calculating duals

Duals are computed using spherical reciprocation. But this requires choosing a centre of reciprocation. For polytopes with a centre of symmetry there's an obvious choice, eg in 3D anything with dihedral, tetrahedral, octahedral or icosahedral symmetry, but not pyramidal symmetry, which has an axis o...
by robertw
Sat Apr 03, 2021 4:11 am
Forum: Stella Forum
Topic: Selecting issue
Replies: 7
Views: 2173

Re: Selecting issue

Is it selecting the same type of element, eg click on a vertex but it selects a different vertex? Or could it select a face for example? Does it happen on all polyhedra? Or only complex ones? Are you saying it only happens in Faceting mode and Measurement mode? Or is it any time you select a vertex,...
by robertw
Fri Apr 02, 2021 5:47 am
Forum: Stella Forum
Topic: Selecting issue
Replies: 7
Views: 2173

Re: Selecting issue

Is it higher DPI? If so it might be that you need to be closer to the point now for the selection to work, ie same distance in pixels but smaller pixels. I can't remember off-hand if that's how it works, or whether it takes DPI into account, but that could be it. Otherwise, not sure. When you say it...