Home 3D Art Showcase & Critiques

Bad Seams on Simple Normal Map?

polycounter lvl 5
Offline / Send Message
Dan Powell polycounter lvl 5
Hi folks,

Trying to bake down what should be a very simple bake, however I'm getting bad seams on the resulting object.

Result:

2404817b37.jpg

LowPoly:

da38494156.png

HighPoly:

39d58082ab.png

UVs:
b9923c719a.png


Cage:
df3774dd4b.png

So far I've tried:

- Resetting the XForm
- Resetting the Normals
- Checked the smoothing groups - UVs are also separated per group
- Reimporting the object and doing the high poly again
- Exporting as obj instead of fbx - same result

Any help appreciated!

Replies

  • tahakitan
    Offline / Send Message
    tahakitan polycounter lvl 9
    I had the same problem one time. this is because of the way it's baked from high to low. to get a smooth transition, the transition angle on the low poly cant be to sharp. anything 90 degrees or sharper causes it. A way to fix it is to give it 1 bevel to reduce the angle transition. this will occur only on areas where the UV edges are not connected.

    point simple, your low poly edge is to sharp/low poly and you need to add 1 bevel in those specific locations.

    If I am wrong than someone please tell me different but that is how I fixed the issue after researching it.
  • Dan Powell
    Offline / Send Message
    Dan Powell polycounter lvl 5
    Thanks for the reply Tahakitan, though I'm not sure that's the issue. I've been baking down very similar objects such as the one below and the normals have come out fine without any bevelling.

    9fdd5115d4.jpg

    I'll give it another go and make the edges on the high poly a bit sharper
  • tahakitan
    Offline / Send Message
    tahakitan polycounter lvl 9
    well lets us know if u find out. :)
  • Dan Powell
    Offline / Send Message
    Dan Powell polycounter lvl 5
    Still getting the seams with sharper edges - I'd try bevelling it but it's not been an issue with any of the other (very similar) stairs so I'm hesitant to do it here as I'm thinking there's something wrong with the mesh or XNormal settings
  • tahakitan
    Offline / Send Message
    tahakitan polycounter lvl 9
    are your edges hard or smooth? I think that causes it also. They should be smooth.
  • tahakitan
    Offline / Send Message
    tahakitan polycounter lvl 9
  • Dan Powell
    Offline / Send Message
    Dan Powell polycounter lvl 5
    Everything on the high poly mesh is in one smoothing group, with a Turbosmooth applied and control loops. Everything in the low poly is set up with "auto-smooth" smoothing groups, and it looks correct.

    The edges are intended to be slightly soft - they're defining a plastic-like material.

    The Normal map bake looks fine, and wherever the smoothing group changes on my low poly I've broken the UV shells, which should be correct.

    2fa13b2dec.png
  • Fwap
    Offline / Send Message
    Fwap polycounter lvl 13
    Did you remember to flip the green channel in Marmoset?
    Maybe try setting the mesh's tangents to 3ds Max as well, in Marmoset.
  • Dan Powell
    Offline / Send Message
    Dan Powell polycounter lvl 5
    Fwap wrote: »
    Did you remember to flip the green channel in Marmoset?
    Maybe try setting the mesh's tangents to 3ds Max as well, in Marmoset.

    XNormal usually produces correct normal maps - they shouldn't need flipping in the Green (Y) channel for Marmoset; though they do for some renderers, such as UE4. However, I have tried this just to be certain - unfortunately it produces even more undesirable results. I've also tried combining different flips of the channels and different tangent spaces in Marmoset, and the results are always incorrect.

    I can't pinpoint what the issue is, but I believe it's one with the actual lowpoly mesh. This hasn't happened with any of the other very similar sets of stairs I've created. :P
  • Dan Powell
    Offline / Send Message
    Dan Powell polycounter lvl 5
    I've resorted to just rebuilding both the high and low poly mesh quickly - it's fixed now. No idea what the problem was and it's pretty frustrating that I could have saved about two hours just by rebuilding it, but I suppose that's just how it is sometimes... Cheers anyway folks.

    4cf52511e7.jpg
  • Fwap
    Offline / Send Message
    Fwap polycounter lvl 13
    Sorry, i assumed you where baking inside of Max.
  • krztyczekpstryczek
    Offline / Send Message
    krztyczekpstryczek polycounter lvl 4
    You can check this video

    https://www.youtube.com/watch?v=ciXTyOOnBZQ&list=UUyKu5CWYWHptg3EMfg3qtVQ

    I think it's clearly explain how to create nice normal maps. Hope it helps:)
  • nimlot26
    Offline / Send Message
    nimlot26 polycount lvl 666
    Those seams appear because you scan with xnormal and you have different smoothing groups. When you set the distance for scan for some reason xnormal will go a bit over the edges and actually render a bit more from the other side. If u have flat surfaces u can adjust the low poly's uvs by moving them 1-2 pixles inside and you'll get rid of those seams ....but the correct approach is to actually make a cage mesh in 3ds max and use it when scanning with xnormal. It will fix your problem.
  • marcobar
    Offline / Send Message
    marcobar polycounter lvl 4
    My texturing teacher always has us use TexTools for Max (it's free), and its "Smoothing Groups from UV Shells" to fix weird edges like this while baking. It's worked for me when I've had similar baking issues to this one. The option is in the 'Tools' dropdown of the TexTools toolbar.

    Aside from that, you could add control edges to the low poly just for baking, and then remove them once you have a clean map. That's quite a bid of fiddling for a simple edge, though.

    Link: http://www.renderhjs.net/textools/
  • Tzur_H
    Offline / Send Message
    Tzur_H polycounter lvl 9
    marcobar wrote: »
    Aside from that, you could add control edges to the low poly just for baking, and then remove them once you have a clean map. That's quite a bid of fiddling for a simple edge, though.

    I'm not sure I'm correct, but I think the workflow you mention is:

    1. Bake an object space map using the modified mesh (with the support loops)
    2. Remove support loops, and export the 'new' low poly
    3. Convert object space to tangent space using Xnormal or Handplane and using the 'new' mesh

    I'm new to this and trying to learn but it's hard when people are dropping crucial parts, no offence.. Again, if I'm mistaken, please do correct me so I and others can learn.
  • C86G
    Offline / Send Message
    C86G greentooth
    Your edges on the lowpoly can be sharp as a blade as long as you split the UVs, bake correctly and got the Y channel correct as well. Then you usually don´t even need support edges for your lowpoly.
  • WarrenM
    You can check this video

    https://www.youtube.com/watch?v=ciXTyOOnBZQ&list=UUyKu5CWYWHptg3EMfg3qtVQ

    I think it's clearly explain how to create nice normal maps. Hope it helps:)

    Just to reiterate ... that is one of the best videos you'll ever see. Once you understand what's being said, you'll never have another bake issue.
  • GRAT0R
    I've been dealing with baking issues since forever untill the last few models.

    My pipeline is similar to yours. The way I solve the issue you present is by setting the lowpoly to only 1 smoothing group and fixing the "shading" issues by adding edge loops, this way you can split the uv's and you won't notice any seam. I think you could delete the loops after the bakes but to be honest I didn't try it myself.

    This problem was very frustating to me and really took very long to understand what was happening and I couldn't find any info that I'd understand on the internet. Also the handplane videos helped a bit on finding this solution, altho I don't find handplane necesary and now my bakes are better than ever.
  • Dan Powell
    Offline / Send Message
    Dan Powell polycounter lvl 5
    Cheers guys - I'll give this all a look at.

    The thing that's caught me off is that this wasn't an issue with any of the other three sets of stair models I'd built, and they were all built exactly the same - rebuilding the mesh from scratch also fixed the issue which does suggest to me that somewhere along the line there was an issue with it.

    nimlot26 wrote: »
    ....but the correct approach is to actually make a cage mesh in 3ds max and use it when scanning with xnormal. It will fix your problem.

    I created a cage in 3DS Max using the projection modifier as always, then exported it using XNormal's SBM exporter - then it uses your projection cage from 3DS Max in the bake.
    Fwap wrote: »
    Sorry, i assumed you where baking inside of Max.

    No worries. :) To tell you the truth I've never baked inside of Max, though at some point in the future I will learn just in case any studios I apply for when I'm out of University don't use XNormal, but it seems to be relatively standard in the industry, as it is free.
    marcobar wrote: »
    My texturing teacher always has us use TexTools for Max (it's free), and its "Smoothing Groups from UV Shells" to fix weird edges like this while baking. It's worked for me when I've had similar baking issues to this one. The option is in the 'Tools' dropdown of the TexTools toolbar.

    Aside from that, you could add control edges to the low poly just for baking, and then remove them once you have a clean map. That's quite a bid of fiddling for a simple edge, though.

    When I created the UVs they were split wherever the smoothing group changed - on simple objects I usually just use the "Flatten by Smoothing group" tool in Max's UV editor then position them from there.
    C86G wrote: »
    Your edges on the lowpoly can be sharp as a blade as long as you split the UVs, bake correctly and got the Y channel correct as well. Then you usually don´t even need support edges for your lowpoly.

    Yep - this was the case with all of the other similar meshes I made.
Sign In or Register to comment.