Friggin' seams won't go away!

d_woo77

So, I've been fiddling with this for a while now and just can't fix those damn seams. As far as I can tell, the Normal map makes them more apparent. Anybody know how to fix this?

For the sake of clarity, the seams appear right along the edge of overlapping UVs that are sharing the same texture space. I'm doing this for a lot of the models parts, but this is the only spot that has this problem the worst. This is the worst spot. The other parts are only apparent under specific angles where the light has to hit it just right. (Minimal but manageable, IMHO).

gilesruscoe

Did you use edge bleeding to allow atleast 8 pixels space between the edge of your UV's and the end of the texture? Mipmaps are likely to be the cause.

d_woo77

Not sure exact. When I did layout the UVs, I did make sure there was some space between them. (I had that happen to me once before, what a disaster) But is there a setting that adjusts the Edge Bleeding?
Also, not sure if that would fix it. As an experiment, I tried shrinking the UV so that is was well with its designated texture space, but the seam still showed up regardless.

AsaNYC

I'm no expert on this, but is there a chance your UVs aren't snapped to a pixel?

Hito

dustinbrown wrote: »

http://wiki.polycount.com/NormalMap#Mirroring

http://www.gamasutra.com/view/feature/1800/completely_eliminate_texture_seams_.php for diffuse maps

Sean VanGorder

Are you baking your maps with only one half of the mesh and then mirroring it afterwards? If so, the normals will bend slightly at the center, causing a seam.

gsokol

What does your texture sheet look like? Also, show us your normal map.

Edit: Oops didn't refresh before posting...looks like other people had the same idea.

sprunghunt

I would suggest just not putting seams there. You could easily break the UVs on an edge where it makes sense such as the edge between the metal and the green fabric.

And the arm just probably should not have a seam running down the outside of the arm. Put the seam on the underside of the arm instead.

EarthQuake

SeanEG wrote: »

Are you baking your maps with only one half of the mesh and then mirroring it afterwards? If so, the normals will bend slightly at the center, causing a seam.

This is the likely culprit, from what I see here for the center seam at the very least.

Proper workflow for baking mirrored stuff:
1. Make sure the entire mesh is there, do not delete half the model and then mirror later
2. Simply offset one side of the uvs exactly 1 unit in the UV view, so they are outside 0-1, this will ensure the texture shows up correct, but causes no problems because of overlapping.

The rest could be any number of issues including:
baking in one app and displaying in another
having and unwelded projection mesh cause seams around hard edges

perna wrote: »

Hito..
no no no do not paint on the normal map
do not ever paint on the normal map
please do not manually paint on the normal map in photoshop
ever
please
that's terrible

Let's lay this to rest and forget it was ever suggested.

Yes yes, a normal map isn't like a diffuse map where you just match up the colors on the seam to fix it, the colors in a normal map correspond to specific mathematical data that tells the mesh what direction the normals should face. Never ever just paint randomly on them.

d_woo77

Ah, brilliant! You guys are awesome. Thank you. I woke up this morning to all kinds of solutions.
So, I'll try to address as much as I can:
- I'm working in 3ds Max and texturing in Photoshop.
- I welded the verts along the said seam so the two overlapping UVs should be perfectly aligned where the should.
- In the baking process, I made a complete high poly and then baked it onto only one half of the low poly (which is naturally symmetrical)

With apologies to perna, I went ahead and retouched the Normal on Photoshop to test the results. Below is an image of what I got. I will like to know other solutions to this problem as it is a reoccurring one. I've yet to check out the links Hito and dustinbrown posted, but I'll post my results for those soon.

d_woo77

This seems to help.

Hito

Yes yes, a normal map isn't like a diffuse map where you just match up the colors on the seam to fix it, the colors in a normal map correspond to specific mathematical data that tells the mesh what direction the normals should face. Never ever just paint randomly on them.

the RGB channels correspond to XYZ in 3d space. 128,128,255 blue will basically inherit the normal direction from the model; while changing R and G values will shift the default normal direction left/right or up/down.

There are disadvantages associated with hand painting the normal map for sure, but it's not absolutely forbidden to modify the normal map in photoshop.

uncle

^It's like doing something wrong and spending time to fix it everytime... So yeah, I agree with above.

ScoobyDoofus

I'm just gonna jump in here and say...Please do listen to Perna and Earthquake. They are absolutely correct. Do not edit the normals by hand, if you can avoid it. You are almost always better off doing it the right way first, rather than fixing errors by hand.

d_woo77

So here's the result from the method EarthQuake suggested. Much cleaner.
With regards to sprunghunt's comments: (I would suggest just not putting seams there.)
Yeah. Boy, did I find that out the hard way with this model. There were a few areas I had to redo for that specific reason. But certain areas were just so symmetrical that I thought it'd be pointless to paint twice.
But I'll definitely be more aware of this mistake on future projects.

d_woo77

Also, my thanks to Hito. The link you suggested with that tutorial on Gamastutra is just what I need to fix similar seam issues made by the diffuse map.

d_woo77

LOL Yes. Yes, indeed.
I'll be redoing other area's where I made the same mistake. Thanks again, everyone!

ceebee

Ya the only thing you should be splitting is the UV islands during baking. I've split character's heads straight down the middle and got super clean bakes by just offsetting the mirrored UV island to 1-1 space or something. Then once you're done baking you just move the islands back into place.

I realize this has been covered, but it's definitely a good practice. Rather than hand painting normals ewughhh

d_woo77

Just thought I'd finish off this thread with the final render. Although, its with bit of irony. The HD renders show a friggin' seam. :shifty:
My guess is that its somewhere in one of the Spec maps or in the reflection mask... *Sigh... This never ends does it. Well, at least I'm better prepared for the next model. So, on to the next project!!

Thanks again to everyone for helping me out!