fearful symmetries

This week I'm rebuilding my home. Why? Because it was my first major build and now I know better. The fun thing about my home (Hexamon House in the SE corner of Zoe) is the hexagonal symmetry. I love the look of it, but it's not the easiest thing to deal with using SL's build tools.

Here is a building technique I stumbled across that helps a lot. I'm sure others do exactly the same thing, but perhaps this will help out some newbies. The upshot is you can do a lot of non-rectangular stuff using hardly any math at all.

When working with hexes, I can always align things so one edge is parallel to either the X or Y axis. I build that side of the room/floor/etc first. Then I put a pivot prim in the middle of the room, exactly centered. (Centering isn't hard if you choose the right orientation to start work.) Link up all the room parts, then link to the pivot LAST. Look at the pivot's numbers in the edit window. SHIFT-drag UP to copy the link set, then type in the old Z value to reset to its original position. Enter 60 as the Z rotation (assuming it started as 0). You now have two sides of the room, and didn't have to do any funky math! Repeat the copy/rotate step until you have six sides. Unlink everything and discard the pivot prims.

Three important points:

1) Linking to a pivot prim gets you a lot of power. You can link up prims that have any rotation or odd position numbers, and link them to a pivot that has nice round numbers for its coordinates. Then you can adjust the pivot - using snap to grid can make things go very vast.

2) Rotating the link set using numbers in the edit window rotates around the center of the pivot prim. This gives a differnent result than using CTRL-drag to rotate using the colored circles - that rotates around the link set's center of mass. DON'T DO THAT! Use the numbers in the edit window and you'll get better results.

3) Let SL do the math for you. Start with the side of the room that is aligned with a cartesian axis, then let the rotation tools figure out everything else. You may have to do a little math for the geometry of that one side, but the rest is easy.

That's a useful technique! I've been tearing my hair out working with toroid sections that insist on rotating around the center of the mostly cut-away torus. This may help. Thank you!

I'm doing something similiar with the tetrahedron (prism) section of the new Ivory Tower Library of Primitives in Natoma. Tetras are extremely hard to tame and align, and I find it absolutely necessary to use a pivot prim to bend them to my will. You can get some remarkable shapes from tetras though.

Lumi

Yep, been doing that as long as I can remember

Yes, good tutorial.

Now for your second challenge, create a semi-circle building with the centerpoint outside of link-range.

And your third challenge, create flat floors.

Circular stuff isn't hard. I've known trig for ages, and I've got the travelling auto-rezzer thing down now. Or maybe I should write a Brezenham script to make a circular wall out of a zillion cubic pixels

Flat floors? I don't get it.

I've found flat floors in large circular buildings to be a challenge. I'm curious to know what works best. By flat floors, I mean floors without texture flash due to overlapped prims and without the jaggy seem visual between prims with z-axis-offset as little as 1/1000th of a meter (to avoid texture flash.)

My solutions have been to deal with the jaggy seems, hiding them best I can... or working with triangles.

Oh yeah, texture fighting is so annoying. I ran into all of those issues you describe, and I think I came up with workable solutions for all of them. Seams haven't been much of a problem really, or perhaps I have a higher tolerance than you do. I made the hexagonal rooms out of prisms (triangle shape), and pivot construction lets all the textures line up perfectly. You can also use a skewed box if your texture is compatible - saves prims and is easier to work with in some ways. I did the same thing with Z offsets of 0.001m to avoid texture fighting for the balconies on the perimeter of the room. I just had to make sure that the perimeter texture of the central floor prim was the same as the top textures of the floor and balcony. It looks fine most of the time, though there is still a bit of a mess from particular angles. I wish you could cut cylinders on a chord instead of just on a radius.

If you want to view my work, it's in the SE corner of Zoe (200,40).

A year ago, I taught advanced building classes where I explained people how to build n-sided polygonal walls. Then I got fed up with the broken building tools and just scripted an autorezzor to do it for me

Yeah, I built an auto-rezzer to do this too. Mine uses scripts in the rezzed objects so you can adjust the radius of the polygon and individual prim dimensions on the fly. Is no one selling a tool like this yet? If not, maybe I'll clean mine up and give it away. I wish LL would just add tools like this to SL.

BTW, when I get difficult seams, some times I just cover them with a long narrow prim. Often you can get it to look like it's just part of the design.