Symmetrical UV problem UDK

Clark Coots

Hey, I've been using UDK for about a week so I'm a noob.

I have symmetrical UVs on my floor pieces and when I import to UDK I get this! I have 3 Floor sections all sharing one texture map (diffuse/normal/spec). Double Vent Floor, Double Stair Step Floor, and one vent one stair step (which works fine because UVs aren't symmetrical). Any ideas how I can fix the symmetrical UV problem this?

sprunghunt

coots7 wrote: »

Any ideas how I can fix the symmetrical UV problem this?

http://udn.epicgames.com/Three/ContentBlog#Fixing specular highlights when using X and Y symmetrical texture mirroring

Clark Coots

thanks, but I've tried that exact technique already. Same problem.

things that I've tried that didn't work:
moving the symmetrical piece 1 full U or V unit.
overlapping UVs with AND without UVs welded at seam
deleting half of mesh, export, import to UDK, duplicate and rotate 180 degrees.
hard and soft edges on and around seamline in Maya

I've also read a lot of this:
http://wiki.polycount.com/NormalMap
but still no success.

One thing I didn't do is mirror geometry THEN bake normals. I baked with half my mesh first. But I don't understand why that would matter. Looking at my Normal map doesn't seem like anything would cause that type of shading, plus it looks fine in Maya

sprunghunt

Another thing you could do would be to try lining up your seam with the seam you have in the texture. So the center section wouldn't be mirrored.

Or you could just not mirror it at all.

also make sure you bake your normals with the rest of the mesh attached.

Clark Coots

I dont have a seam in my texture, its basically a full texture for the half stair case half vent floor piece. then I just reuse the texture (only half of it) for symmetrical floor pieces. theres no seam in the texture and the UV seam would just be in the middle where there isn't any crazy normal map information.

sprunghunt

coots7 wrote: »

I dont have a seam in my texture, .

What I meant was the textured-on seams in the panel. I see two of them - with a row of rectangular fasteners down their side.

if you split your geometry there it won't be as noticable. In general putting seams on flat spots in your texture just makes it more obvious.

Clark Coots

hiding the UV seam in the seam of the texture was a nice workaround. It's still not perfect, but the floor looks a lot better although the darker metal trim where each floor piece meets looks bad. I think I will resort to individual textures for each of the floor pieces. Nothing is good enough yet. I've got a whole new can of worms with the lighting however. I have pretty simple geometry yet I'm getting terrible shading artifacts. Looks fine before building the lighting, once I do build this is what I get.

sprunghunt

are you using lightmaps on those objects? and are they unrwapped for lightmapping?

it looks like you're using per-vertex lighting

Clark Coots

I didnt make separate UVs for a lightmap. So I'm guessing unless UDK auto generates a lightmap that I am NOT using a lightmap? Also I have no idea if i'm using per-vertex lighting either. Perhaps a link to a good lighting in UDK tutorial would help a lot. Like I said I'm a noob, all I did was go to Build - Lighting - settings check are, Build BSP, Build Static Meshes, Quality(Preview), Use Lightmass. Also my World Properties settings are default and anything else thats I'm missing as far as lighting is set to defaults. Hey thanks for the help so far sprunghunt!

Ouija

If you don't specify lightmap UVs, UDK assumes vertex lighting. There's nothing more to lightmaps than making an additional UV map with uniquely unwrapped islands - that is, no UV stacking like you did. The static mesh editor has an option for doing that automatically if you don't feel like mapping it twice yourself - just click "Generate Unique UVs" and play around with the settings to get some right results. The spacing should be a little bigger than a regular map due to low res nature of lightmaps. Make sure you use slot #1 if you used only one map from the start, as UV map IDs start from 0. (zero being the map you unwrapped) I think that every lightmap slot is automatically assigned to map 1, but you can change it in the properties if for some reason it isn't that way. Once you generate the UVs, rebuilt lights to see how it looks. It should work.

Clark Coots

Ah thank you! Creating a lightmap gives a much better result. There is one more problem though! haha. The Light map is active at a very close distance, but then it seems to resort to a different type of shading when taking a small step back. It's alittle noticable in these still images, but in motion its clearly obvious the shading changes.

I'm guessing its an LOD thing where it doesn't use the lightmap at a certain distance, but that seems silly because my scene is to scale and the default distance doesn't make sense. Could be something else because I've played around with any number I can find associated with LOD. I'm hoping you guys know. thanks.