Tips for building a icosahedron (geodesic) dome?

Looking to build a 4v or 5v geodesic dome out of equilateral triangles (probably using the tapered cube technique for the triangles). Any suggestions for the best way to do this? Should I just look to write my own script in LSL or are there any existing tools or scripts that I could use to save me some time?

Look for shape gen.

Its an awesome tool.

I made a 60m sphere with it that looked cool.

I'll check that out. Seifert Surface, who has a beautiful geodesic dome on his property, recommended using Blender with the 3D Model Importer script to do this, so I'm looking into that as well.

Yes, one of blender's default shapes is the "icosphere", which gives various (but not all) sizes of geodesic domes based on the icosohedron.

I've tried the blender script from here:

http://members.aol.com/demalion2/geodesic.html

It seems to generate really nice domes. I haven't tried the import yet. Is Prim.Blender (http://sourceforge.net/projects/primdotblender/) the best way to get the model into SL?

Good find!

I don't think Prim.blender will do what you want. Prim.blender lets you edit with blender objects that act just like prims in SL, then import those blender objects into SL as SL prims. To import a mesh needs something to do triangular prims for each triangle of the mesh. For obj files, that would be another of Jeffrey Gomez's creations, Facemaker .

Thanks again for the help, Seifert! I just posted that same question in the prim.blender thread. I wasn't sure if prim.blender was the successor or not to the Facemaker script. Sounds like it isn't.

ShapeGen doesn't do Bucky It could, though, for the math able.

Do you know enough math and programming to write the scripts that say where each piece should be in three space? Then a script that whomps out a dome would be the best way to go.

ShapeGen is open source, and it probably has lots of utility functions within that would help you.

Lee, thank you for the clarification about ShapeGen. My first job out of college was as a programmer at a software company that made a parametric design CAD system, so I do know a little bit about such things, but I'd still prefer not to write it myself unless i have to. I'm going to try the blender to facemaker approach first and then if that doesn't work, I'll try to cobble together a triangle rezzer using the ShapeGen code as a starting point.

I've been working on my own dome generator. It operates using square/trapezoidal panels. Currently does up to 10 meter radius, I plan to enhance it to do up to about 80 meter radius, but not taking the time this week to do that. I currently have a dome it created, on my property. This will drop you just outside it.

http://slurl.com/secondlife/Cottonwood/205/250/106/

I plan to make it somewhat larger and with more facets, before I really build it into a house. If this looks like what you would like, let me know. I doubt I will be on much this week. However after the beginning of the year, I will probably be spending some more time in SL. Once I do some tweaking, I could use it to help you build a dome.

Just wanted to post a follow-up to say that I just tried out the approach of generating the dome in Blender using the geodesic script and then importing it into SL via Facemaker (using Christopher Omega's notecard driven version). It works beautifully and resulted in a very impressive looking dome. I just need to figure out the scale issue, it's exactly half the size in SL as it is in Blender.

I think the size may be because you are rezzing from a 0.5m cube? The script scales the output based on the size of the rezzer, so it may just be that.

Yes, that was the problem. Setting the root rezzer to be 1x1x1 fixed it. Good to know, I can use the same rezzer to build different sized domes.

Emma, I'd love to see the outcome of this, I've been building polyhedra by hand (building the net out of prims with a prim at each vertex and link-rotate link-rotate (ad infinitum) to roll the polyhedra). The outcome lacks some accuracy as the rounding errors with rotations and positions are compounded during the process.

to see some of my polyhedra inworld visit:
http://slurl.com/secondlife/Lasiocampa/173/197/27/?img=http%3A//www.sluniverse.com/snapshots/124810.jpg&title=nand%20Nerd%27s%20Flexi%20Fun

Also, Brian, I took a look at your sphere, looks good. Took me much longer to manage a sphere that looks that good. Max sphere size I've made so far is 256m diameter using around 6 thousand primitives! (see http://www.sluniverse.com/pics/pic.aspx?id=117561&sort=Pictures.PictureID+desc&Name=nand+Nerd )

You can see a picture of it here:

http://www.flickr.com/photos/25909119@N00/330422797/

I'll try to upload a few more pictures. If you want, IM me in-world and I can send you the rezzer for it.

I'm pretty sure it's been done entirely in SL before numerous times (as opposed to importing coordinates from Blender or whatnot), but here are the results of my adventures in geodesic dome generation via scripts (with a BIG thanks to Seifert Surface's triangle rezzing function from his parametric surface generator):

- planning + icosahedron rezzing

- subdivision of faces + generation of geodesic spheres

Right now, the script is rather inelegant and doesn't take advantage of the "symmetries" of the icosahedron, which means it could probably do 20-fold less computation just by using the face symmetries. And I haven't cobbled in anything that has it make domes, instead of spheres.

I'm not sure if I'll release the source code yet. (On the other hand, I doubt there's much of a market for giant prim-consuming domes and spheres... Anyone want to buy a sphere? Only L$1 per triangle!)

Nice work Ged, wish I had the patience and knowledge to even begin scripting a device to rez icosahedral spheres/domes.

After seeing Emma's demonstration of the prim importer together with Blender and a geodesic script I replaced the bucky ball dome I had been using with an icosahedral sphere (well, half of one anyway).

Very cool! I started down that path and then took the "easy" way out with the Blender import script. I agree that with the number of prims involved, it's a bit of a guilty pleasure to build these things, but they look so beautiful and watching them rez is a lot of fun.

Mephistopheles Thalheimer has also been making a geodesic sphere rezzer based on that triangle rezzing thing, I think he plans to release the source, so you might not have a choice Ged

Re: your blog, here's one thing you can do with a 1280 prim sphere

http://slurl.com/secondlife/Gluphisia/63/63/263/

LOL, no worries. For a geodesic sphere rezzer the challenging part is the triangle rezzing part that you wrote... Everything else is just collecting the coordinates for an icosahedron, and then dividing each triangle into more triangles, and scaling it outwards. Not much coding at all.

What would be much more interesting, I think, would be if someone came up with a way to map textures nicely onto a geodesic sphere. There was another thread where someone was hoping to build a large planetarium using a geodesic dome. Not even sure how one would go about mapping fragments of a texture onto a spherical object, when each triangular face would be composed of pointed squares which may be of variable orientation... And, the limited resolution of a single texture would require breaking up the texture into multiple texture files... Somehow I don't think it's going to happen.

=====

Incidentally, I came across your sculpture garden for the first time a few days ago... now THOSE creations are much cooler

IIRC Qarl Fizz was doing something along those lines to make a spherical movie screen.

Cheers

hmmm, come to think of it, if all you wanted was a spherical (or whatever the 3D term for the chord of a sphere) screen to project textures on, it probably wouldn't be THAT hard to make it out of nearly-square trapezoids...

an icosahedral/triangle-based geodesic was just because they _look_ more elegant, but they are much more prim-wasteful, and likely more of a pain to texture...

i'll keep an eye out for Qarl Fixx and the SL IMAX theatre screen

something along this line perhaps: http://www.nandnerd.info/images/sandboxIslandSphere.jpg

And I'd love to see some massive spheres with nicely applied textures. Count me in when handing out the landmarks for your one when it's done Ged.

I've created another dome builder script, you can get it for free at http://slurl.com/secondlife/Gyeonu/249/31/301
It looks like this:

The SURL has changed, and may change more often. Search for "Shine Renoir", click on profile, then Picks and "My Home", teleport to this location and you'll find it for 1 L$ (to monitor if there is any interest in it) completly mounted in sample objects.

The scripts, only, can be found at http://www.sparticarroll.com/Geodesic+Dome+Builder.ashx