UV island seams

Dismembered

So I have been searching this forum and the UDN forums for a couple days to try to figure out this problem but I can't seem to find a fix.

Everywhere that I have a UV island/smoothing group I get a horrible seam.

• I used max to bake all my normals (I can't seem to get xnormal to work for me)
• I have exported from Max using multiple formats (FBX, ASE) When using FBX I checked the box to use explicit normals
• I have tried inverting the green channel on my normal map (Some were saying to do it for xnormal maps, so I figured it couldn't hurt to try)
• I have a separate unwrap for my light map (tried multiple resolutions)
• I imported my normal map using TC_Normalmap and TC_NormalmapUncompressed
• I have tried using Full Precision UVs and also tried not using them
• I can view the model in max, using Xoliul's shader, and it looks fine

I can post more pictures if needed, but I guess I will just start with the one showing the issue I am having. The numbers are showing how the smoothing groups and how the UVs are split. The top-right and the left pictures are both from the Static Mesh Editor. The lower-right is viewed in the actual level itself.

Any light shed on this subject would be great, thanks in advance!

Wonkey

If it looks fine with Xoliul's shader, maybe it is the light map? Could you post it? Wish I could be more help

rasmus

As far as I know, Unreal WILL give you slight seams wherever you split UVs. Yes, it completely sucks.

Dismembered

rasmus - I am not sure about that. I am definitely not a UDK expert by any means. But I looked through the assets of The Bathhouse and from what I can tell on his assets is that he has seams set up in his UVs for both his light map and his texture map, and he doesn't have any visible seams on his models. Unless I am completely missing something it seems that you can have UV seams on not get the seams that I am getting right now

rasmus

Well, there are two different possible issues here, as I see it:

1. If you have hard-edge meshes with correlating separated UV islands and try to do bevels in your normalmap from the hipoly this way, as far as I know, Unreal will not display your normals correctly as they would appear in Max when viewed with qualified normals or other correct display methods. See these posts on the subject: http://www.polycount.com/forum/showthread.php?p=1399379#527 Then again you say things look fine with Xoliul, which leads me to believe its...

2. UDK documentation states that you will always get slight lighting seams where you have seams in you lightmap UVs - have you tried keeping your UVs for map1 (diff, normal etc), but making them one unified chunk for the lightmap? That may well help. Posting your UV layouts for all channels would help too

Dismembered

I have tried making them a unified chunk to see if that would affect anything (at least as much as possible so there isn't horrendous stretching) And it didn't change anything. I can post my UVs later as it is kinda late.

Thank you for your continued effort, as I have exhausted all the avenues I can think of.

rasmus

That's mysterious... In my mind it pretty much has to be one of the two things I mentioned, unless it's something stupid like "i forgot to weld my verts", but then you'd see much worse things than these arguably tiny seams you're getting.

Just out of curiosity, do the seams persist without your detail normals?

Dismembered

To answer your latest question yes, the seams do still show up without the normals applied.

So here are my UVS, I chopped off the unnecessary part of the UV maps to save some space. The top UV section are the UVs that I used to paint my diffuse, generate normals etc. The painted red chunks are where you see the seams in the picture, the side vent thingy.

• The bottom left UV section is where I welded the UVs together to make it a continuous shell for the light map, and below it is the corresponding model in UDK.
• The bottom right UV section is where I left them separate, and below it is the corresponding model in UDK.
• Both of them have the same material applied, just a diffuse, specular and normal. No multipliers or anything special in the material. Both also have light map resolutions of 128. I did view it without a spec map and it looked the same....just less shiny
• Ignore how crappy the light map unwraps are I just did a quick version to do the test and show you the UVs.

Could I have missed something while creating this in max? Or is there a step I missed importing this into UDK?