Stella FAQ (Frequently Asked Questions)

Contents

• General questions
• Installation problems
• Questions about using the program
• IAQ (Infrequently Asked Questions)

Q: I want to try it.

A: Go here.

Q: I want to buy it.

A: Go here.

Q: Can I add a link to your web site?

A: YES! Please do! You might even want to put the Stella logo beside it:

Q: Does Stella4D only include 4D stuff?

A: No, it also includes all the 3D features from Great Stella. If you have Stella4D, you don't need Great Stella.

Q: What's the difference between Small Stella and Great Stella?

A: Great Stella has all the uniform polyhedra built in (not just the Platonics, Archimedeans, Kepler-Poinsot and convex prisms). It also has pyramids, cupolae, cuploids, and cupolaic-blends built-in. It has advanced features for creating new models too, including stellation, faceting, augmentation/excavation/drilling, finding convex hulls etc, and it can export models to various 3D formats.

Q: What's the difference between Great Stella and its demo version?

A: The demo is limited in many ways. It only has a limited set of built-in models (the other ones remain in the list but are greyed out, so you can see what you're missing). It only allows features such as stellation, faceting, and augmentation/excavation/drilling to be applied to an even more limited set of models.

Also, the demo version can only export the cube to the various 3D formats, and will only allow printing for the Platonic solids. For example you can print nets for the dodecahedron. Print preview is available for any model though, so you can see what the print-outs would look like (which is often a bit different from what's normally on the screen).

Q: What platforms does it run on?

A: Windows 95, 98, ME, NT4, 2000, XP, Vista. You should set your display for at least 16-bit colour. You can still run it on an 8-bit colour display, but you will get screwy colours, and even the toolbars use 24-bit colour images.

Q: Can I run it on a Mac?

A: Not directly. You would need a Windows emulator, like Virtual PC or the newer Parallels (plus I think a Windows OS like XP). Ironically, my first two sales were both to Mac users!

Q: What can't it do?

A: Here are some things that would be nice, and I may consider adding in the future:

• The algorithm for generating nets worked quite well for uniform polyhedra, but could be better for the Stewart toroids. I have a few improved heuristics in mind for combining faces differently into nicer nets.
• A way to create compounds of polyhedra. You can already create many compounds, but a specific interface for this would be nice.
• Tabs for the nets. I've really found I don't need these though since I leave a tab at every free edge around a net and glue the two tabs together at an edge. This method generally produces the nicest models in my opinion. For more details, see this question below.
• A mode for measuring angles between various parts. Currently there is a mode for measuring distances between points, but angles would be useful too.
• Canonical polyhedra.

Of course, the complete list of things it can't do is infinite (but getting smaller)!

Q: (Usually on a laptop) Why are my windows all white? Or why does it crash as soon as I run it?

A: Some graphics cards seem to have a problem where some windows get drawn as solid white, either always, or after changing the view layout one or more times. Some graphics cards can even cause the program to crash straight away! These problems are more likely to happen on laptops. The Savage S3 graphics card has caused both these problems. For that card, right-click on the desktop and select Properties from the menu to open the display properties. Select the Performance tab. A slider lets you turn hardware performance up or down. Turn it down to a lower level. The description for the level you want might say something like this: "Basic acceleration functions: Use this setting to correct more severe problems, such as unexpected errors in programs.". (Yes, it actually says that!).

Q: Are tabs printed on nets?

A: No. Maybe someday, but I don't think it's too important. You just need to remember to leave tabs on edges as you cut out the nets.

There are three ways people might make models:

1. No tabs - held together with either sticky tape, or even glue along the edges. Requires thicker card I think.
2. Single tabs - at each edge to be connected, one face has a tab and the other does not, the tab being glued under the other face.
3. Double tabs - both faces have tabs, which are glued to each other (leaving it "ribbed" inside, with tabs poking into the centre of the model).

Only with method (2) do you need to think about which edges have tabs and which don't.

I use mostly (3), with (2) occasionally for edges with very sharp angles, or where there's not much room in the net for cutting out two tabs.

With method (2), it's usually not hard to figure out where to leave tabs anyway. In particular, when the whole model is made of a single net, you just put tabs on every second edge around the outside silhouette of the net.

But I do recommend method (3) for most cases. In this case you just leave a tab on every edge. With tweezers it is easy to squish the tabs together (it's harder when gluing one tab under another face), and glued edges look more "symmetric" and precise. Also, when gluing a tab directly underneath another face, the face can often become wrinkly from the glue. It's also often somewhat easier to put that last piece in!

When I use a mix of (2) and (3), I try to glue all the (2)-style edges first, since they are easier to do near the start.

Let me know if you think printing tabs is important, and I might add it sooner rather than later.

Q: Why can't I see the great dodecahedron in the base+dual compound view?

A: It is hidden entirely within the small stellated dodecahedron. This is correct. The dual is made by spherical reciprocation about the mid-sphere (the sphere touching the mid-points of each edge of the uniform polyhedron). I won't explain these terms here, but this method leads to the great dodecahedron being entirely hidden with the small stellated dodecahedron.

Q: Why do some dual models look the same? Is it a bug?

A: It's not a bug, some duals of different uniform polyhedra do in fact look exactly the same. Their faces only differ inside the model where you can't see it. One way to see the difference is to select a face, which makes it highlight in white and show partly transparently through the other faces. Then you can see the difference. Also if you explode the faces apart (Ctrl + Shift + left mouse drag) you can see that they are different shapes.

Q: When I use "Stellation->Enumerate" with the icosahedron, shouldn't I get 59 of them?

A: It depends what criteria are used for accepting a valid stellation. The Fifty-nine Icosahedra uses Miller's Rules, but the default is set to Fully Supported. To see which criteria are available and change to a different one, have a look at "Stellation->Stellation Criteria". Changing the selection here will affect how many stellations are found when you enumerate, and affects which stellations you see when using the Up and Down arrows.

Q: When I use "Stellation->Enumerate", why does the time remaining always get bigger?

A: To figure out how long there is to go, it needs to guess about how far through the enumeration it is. Of course, if it knew exactly how far through it was, then it would already know the answer! It is very difficult to guess how far through you are. The time remaining increases as it gets a better idea about how many stellations are left to count. Depending on the model and the stellation criteria chosen, it may take a second, or a day, or a thousand years or more to come up with an answer!

The estimate is currently not very good for Fully Supported stellations, but it is much better for Miller's Rules. You can select this criteria using "Stellation->Stellation Criteria". Now when you enumerate, many models will tell you how many millions of years remain!

If you have a question that isn't answered above, then you can send me a message. For general questions about what stellation means and other polyhedral matters, you will find a lot of information just by searching the internet. Also see my paper which covers a lot of the techniques available: See Stella: Polyhedron Navigator.