How do I make this star?

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Philip
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How do I make this star?

Post by Philip » Wed Jul 17, 2013 12:14 pm

Hi all,

I've been using Great Stella for a short time. I saw this in an article and would love to make my own but can't seem to get the same dimensions in GS.

Image

I've gotten close by using the "Morph duals by sizing" option but not identical. It looks like a compound of a Great Stellated Dodecahedron and Stellated Icosahedron, where the latter has a smaller outer diameter.

Any help would be appreciated.
Last edited by Philip on Tue Jul 30, 2013 1:40 pm, edited 1 time in total.

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guy
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Post by guy » Mon Jul 22, 2013 8:13 pm

Hi,

I cannot see the image of the star, it just shows a small box where the image should be.

Philip
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Post by Philip » Tue Jul 30, 2013 9:39 am

Image

The link was broken for a bit. Here you go.

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robertw
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Post by robertw » Wed Jul 31, 2013 5:58 am

What was the article about? Is there a link? Might help to identify it if the article explains anything. It's not a great stellated dodecahedron because the triangular peaks are twisted half way around, and it's not a great icosahedron because the angles are wrong. It could be a generic nothing-in-particular, or maybe a stellation of something. Almost looks like it could be a stellation of the rhombic triacontahedron, but the angles don't quite look right for that either.

Philip
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Post by Philip » Wed Jul 31, 2013 10:17 am

This is the closest I've gotten.

Image

I can't seem to lengthen the star point in relation to the triangular part. I've been using all the different methods for merging compounds. Maybe I've missed one or two ways of doing it.

Philip
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Post by Philip » Wed Jul 31, 2013 11:48 am

The article was on Magnus Wenninger. I can't find it online anymore. I also contacted him for the GS file but he didn't have it.

Is there an option in GS to stretch selected points out while leaving unselected points as they are?

Here it is from another angle:

Image

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robertw
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Post by robertw » Wed Jul 31, 2013 2:58 pm

I came pretty close. I don't think it's a stellation of anything in particular, and the angles are too steep for the components to be either a great rhombic triacontahedron or a great icosahedron.

I made each part separately then added them together after trying a few different relative scales. To create one, start with a great stellated dodecahedron and augment all faces with a pyramid, then Ctrl+Left-drag to make the peaks a bit higher. For the other one, start with a great icosahedron and augment all faces with pyramids again, and again Ctrl+Left-drag to make the peaks a bit higher. The extent of the peaks in both cases was just judged by eye. If you got it right you could recreate Magnus's model exactly in theory, but who knows how he did it.

Here's the .stel file

Image

Philip
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Post by Philip » Wed Jul 31, 2013 11:10 pm

Got it. That's great. Thanks for the help.

Image

One question: I'm using Great Stella 4.4. Are tabs included in Great Stella 5?

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robertw
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Post by robertw » Thu Aug 01, 2013 10:25 am

Version 5 can indeed show tabs on the nets, including in the 3D folding view, the 2D unfolded view, and when printing too. You can choose between double-tab, single-tab or no tab methods, globally, or even per edge.

There's also many other major additions. See here:
http://www.software3d.com/History.php#50

Rob.

Philip
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Post by Philip » Sun Aug 11, 2013 9:52 pm

Thanks for all your help Rob. It turned out well.

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