Texturing Arches

Some background: I'm working on a build that has a large number of arches. They're primmy ones, too, not just hollowed boxes: the arch itself is, in each case, a cut, hollowed, and stretched cylinder. They're also meant to be brick arches, so I made up a brick arch texture. Essentially, I made a rectangle and drew rays out from a central point at the bottom, each ray an equal number of degrees past the previous ray (except for the capstone, which was made a bit bigger). Like putting slices in a pie. Except, er, it's square, and only half the pie's there. Anyway, each resulting wedge of the rectangle became one brick. It looks pretty good when applied to the front of my arches.

My problem, though, is that I'm finding it impossible to properly texture the undersides (and probably topsides, though I haven't gotten there yet) of the arches. I can't get the bricks underneath to match up with the bricks on top. I've tried four different techniques, I've switched between planar and regular mapping on both the front and underside of the arch, and it's still not working. I think I'd have better luck if my arches were perfect semicircles, but that's not something I'm willing to do. Does anyone have a magic fix for doing this kind of work, or at least some tips? Or am I out of luck?

Thanks.

The inside of an arch is mapped cyllindrically so your best bet would be to make the same number of rows for the inside arch as you have radiating out from the center for the face of the arch. They should be evenly spaced (with the center one a bit larger to match your capstone). The actual width of the rows doesn't matter as long as they're all the same (not couting the capstone). Set the horizontal tiles to two and then adjust the offset to get the seams at the bottoms of your arch (otherwise half your rows will be on the cut portion of the arch). If the cut on your arch prim is 180 degrees you should be able to get a match without too much trouble.

I suspect the problem you're having is that the width of the grout compared to the width of the bricks is smaller towards the center and larger towards to outside of the arch. It may take some trial and error to figure out what the grout width compared to brick width needs to be on your inside texture.

I can barely picture this since I have ratbrain, but I have a feeling no ammount of scaling or shifting will make the same texture match.

You have to create a different texture to accomodate for the distortion, since you mentioned that its not a perfect semi circle.