Wednesday, January 17, 2007

geodesic domes in second life

Success, the geodesic dome script actually works!

(looks like a Blue Poseball got very angry at me...)

As I mentioned yesterday, the domes start off as a 20-triangle-faced object, an icosohedron. To make it geodesic, you take each triangle, and split it into n^2 smaller triangles, and smooth them out to the surface of a sphere.

So, for increasing values of n, you get more triangles used to form the sphere:
- n=1: 20 triangles (what I had yesterday, an icosahedron)
- n=2: 80 triangles (the one I'm trapped in up above)
- n=4: 320 triangles (the bottom one, but using larger triangles)
- n=6: 720 triangles (shown below)

I wrote it to be fully scalable, so that you could make the spheres / domes as big as you want. I'm not sure how many prims it would take to crash the sim, so I didn't try to make any bigger than 720 triangles, although I know people have made ones in SL with more than 1,000 triangles. Still, with a prim size limit of 10 meters, using 720 triangles would allow you to make a sphere that was >90 meters across, or 360 triangles for a dome, which is more useful for a build anyhow.

Rez in progress, for a 720-prim sphere

All done! Behold, the Blue Poseball of Doom!

This one actually uses fewer (320), but larger triangles, so the completed sphere is larger than the ones above.

OK, this is just about the largest geodesic sphere you can make with 720 triangles (the triangles are nearly maxxed out at 9.8 meters). I can't zoom out far enough to get the whole thing in. Trying to make it bigger started running into problems of encroaching on neighboring sims, so I don't think I'll try to do the 1280-prim sphere.

"That's no moon... It's a... giant blue poseball..."

But, that still leaves the question... What do I do with these things now?