My map has lamps made from cylinder meshes folded in on themselves to make rims. gtkRadiant renders this as a smooth, round surface. But somewhere in the BSP phase the cylinders turn into hexagonal tubes.

Why is this happening?

Stranger yet; there are a few places where lamps stay round like they're supposed to do. These lamps are supposed to be identical, but with different positions and angles.

Anybody know what's going on here?

I am using MacRadiant 1.4 and q3map2GUI. The only tabs used in the BSP phase are -meta and -patchmeta.

The -patchmeta switch converts patches into "real" geometry.
Quake 3 uses LoD on patches, so if you're far away from an arch, the arch may be rendered out of 16 triangles, but as you move closer, the LoD gets higher and more subdivisions on the patch are rendered, resulting in a smoother curve.

these pictures show curves in quake3 rendered with different subdivision values:
http://www.planetquake3.net/tweak/bench ... sions1.jpg
http://www.planetquake3.net/tweak/bench ... ions40.jpg
http://www.planetquake3.net/tweak/bench ... ions80.jpg
http://www.planetquake3.net/tweak/bench ... ons120.jpg

The -patchmeta switch now "bakes" a LoD depending on size, distance and curve complexity of your patch into your bsp. The curve gets converted into "standard brushes", and won't change its subdivisions at any time. I don't know if Nexuiz supports the q3-way of rendering patches at all, but i don't think so (so no LoD on patches).
I believe that's why your curves don't look smooth. Because the standard LoD that q3map2 chooses to "convert your patches into brushes" is too low.

But you can force a set LoD using -patchmeta N
(iirc N should be something like 4 or 5 default)

Or don't use -patchmeta
(Of course -patchmeta can be useful in some maps, especially because Nexuiz tends to create some leaks on the edges of patches that don't occur with -patchmeta (happened so in reslimed for example), so forcing a LoD with -patchmeta could be the better alternative.)

Strahlemann wrote:But you can force a set LoD using -patchmeta N
(iirc N should be something like 4 or 5 default)

I didn't find any -patchmeta N option, so I tried

-patchmeta -subdivisions N

That fixed it. Thanks. Everything is now as round as can be.

(always wondered what the subdivisions switch did)