avoiding normal issues in UE3?

Funky Bunnies

Hey all, I know there have been countless questions about normals and UE3 but I thought I'd get some insight on my particular issue as I simply can't wrap my head around it.

I realize that UE3 can't handle mirrored normals well, but the larger issue is the normals on my separate uv islands.
Here's what I'm getting:


the one at the right is just a flat grey in diffuse so you can see the shading issues.

with a blank normal map of 128,128,255, I still get this result:



AND so in all my vast noobdom, I ask you good sirs: How can I remove these normal issues at each uv shell?

nrek

You might want to check out the solutions that were posted in this thread and see if they help. Good luck http://boards.polycount.net/showthread.php?t=56197

gamedev

Keep your mirrored normals to the x axis only. As well, what you see in the model viewer is always worse than when it's fully baked with a lightmap. Your lightmap uvs should be well spaced too. As far as I've experienced, the seam will never be gone just greatly reduced. As for the seams on the separate uv chunks not sure what's going on.

Funky Bunnies

thanks all,
I've tried with the mirrored uvs ontop of eachother, shifted +1 or -1 in U and squished into 0-1 with a 2:1 map which all result in variants of the same problem.
The results are also the same after building and playing.

The mesh is all merged and everything too. I thought maybe my normals were screwed upon export, but there aren't too many options I could have messed up

JohnnyRaptor

ue3 doesnt support mirrored normals per say, you cant mirror from the center of the mesh, but only slightly over the center seam. so 2/3rds has to be unique and 1/3 overlapping

whats_true

I found this very useful mate.

http://boards.polycount.net/showthread.php?t=51088&highlight=normal+map+ut3

Funky Bunnies

i've heard that, JohnnyRaptor, but ive seen totally mirrored meshes like warby's work in ue3

I don't think the issue is the map because when i squish the layout to a 1024x512 with unique uv's it still has this issue, and even with a completely blank normal map i still get this result


but it's only mild when i have no normal map at all on it. Could it still be a problem with the map? or is there something screwy with my vertex normals

SHEPEIRO

what app are you exporting out of, maya often has "tweaked" normals they lok fine in app but then you export and they are not, try exporting without normals ticked, bring back in and smooth.

MoP

Also have you made sure that your normalmap texture is correctly flagged to be compressed as a normalmap?
I've heard of this issue before, by default UE3 will just load it as a standard RGB texture, you have to enable a checkbox somewhere (not sure where, I haven't used UE3) to make the game treat the texture as a normal-map. Apparently that fixes these issues.

Funky Bunnies

Thanks for dropping by,

I hadn't heard of that issue, Shep. thanks for the heads up.
I'm exporting out of 3ds max and i've tried dumping my normals,redoing them, or exporting them - but it still leaves me with this same issue.
I also hadn't heard of that normal map compression issue MoP, thanks for the tip.
I tried changing the normal map compression in the texture viewer, but it seems to leave me with the same results in this case.

I must be doing something fundamentally dumb and wrong...

EarthQuake

This looks more like unwelded verts or wierd smoothing groups more than anything to do with the normals map. Try welding your uvs, making sure everything has the correct smoothing. The pictire with the flat normals looks like it has incorrect smoothing, i dont know anything about UE3, but in our engine if i were to get that with a falt normal it would be incorrecly set mesh normals, or maybe unwelded UVS.

Kovac

Ultimate possible fix for this (drove us insane with a mirrored head), re-add the actual normal map texture (don't just do it in the material) and make that sucker two-sided and give it the appropriate compression.

Edit: Also make sure that it isn't a material instance but just a regular material... that solution doesn't seem to work with instances for some reason.

Funky Bunnies

oh man, good call Kovac. You and MoP were right.
I guess if you don't apply the correct settings upon import (rather than changing it after import) it'll filter the colors regardless.

Thanks a million to you all