You're making me hard. Making sense of hard edges, uvs, normal maps and vertex counts

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  • Quack!
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    Quack! polycounter lvl 13
    Gradations in your low poly like that get translated to your normal map bake. So to fix that in unsynched workflows you need to work your low poly to match your high polys smoothing a bit closer. You can do this via adding more geometry through chamfers, or you can split up your smoothing groups, instead of using 1.

    I recommend, that if this is a hero/portfolio object, to just spend the extra triangles and add some smart chamfers to ease the smoothing.
  • CougarJo
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    CougarJo polycounter lvl 6
    I need help :(

    -Symmetrized meshes
    -Hard edges along UV seams (I tried with soft edges, it's worse)
    -Uv are not overlapped for the bake
    -It's an FBX export in Xnormal
    -Triangulate before bake


    I tried with maya cage, xnormal cage, custom cage, and I have the same errors, not matter which.

    I tried in OBJ, nothing change.

    On some meshes, everyting is fine, I don't understand!

    yqcq.jpg
  • WarrenM
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    WarrenM Polycount Sponsor
    You're SURE those verts are welded?

    The issue on the left looks like unwelded verts and the one on the right looks like your cage wasn't pushed out quite far enough to encompass the high poly entirely.

    But, of course, I could be wrong. And likely am...
  • CougarJo
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    CougarJo polycounter lvl 6
    Yes they are welded!

    And for the artifact on the left, I've checked, the cage is good, the artifact isn't symmetrical, and it appears ONLY in marmoset toolbag! I don't see them in the xnormal viewer!
  • WarrenM
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    WarrenM Polycount Sponsor
    Is it in the normal map? Like, load it up in Photoshop ... Is it there?
  • CougarJo
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    CougarJo polycounter lvl 6
    Nope, it's not! I have the same bugs on another meshes, nothing on the map, nothing in xnormal viewer, but it's here in marmoset!
  • WarrenM
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    WarrenM Polycount Sponsor
    Uh OK ... well, I have no experience with marmoset so I'll have to walk away now. :) But, hey, it's not your bake...
  • Farfarer
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    Farfarer Polycount Sponsor
    As far as I know, Marmoset has it's own proprietary tangent basis, so I don't think you'll get anything synced to it perfectly.
  • CougarJo
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    CougarJo polycounter lvl 6
    Maybe, but I think it's ok, I've done bake before, and it was fine :(


    Thanks for the help though WarrenM :)
  • .Wiki
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    .Wiki polycounter lvl 7
    I´ve did a recent bake with 3dsmax and imported my model and normalmap in marmoset, it was perfect. So I think it is "synced".
  • CougarJo
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    CougarJo polycounter lvl 6
    For example :

    This, mesh with the WRONG normap map on it, have the same kind of artifact! Good or wrong map, the artifacts is here!

    I presume it has no relation with the map!





    EDIT : in OBJ I haven't this artifact! Must be my FBX export :/





    1s8k.jpg
  • s6
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    s6 polycounter lvl 8
    Bit of a basic question, But I assume you've frozen transforms before exporting, And turned off two sided lighting to check for any flipped faces or goofy normals?

    If the problem persists i would try exporting as an OBJ. Then import it back into maya. Then out as an FBX. Or possibly the FBX converter I've heard about a few times.

    Or you could just export an MB file and import it into a new scene to try and clear whatever weird geometry history might be going on.

    Would you mind posting an image of the model with no normal map in marmoset? just the low poly.
  • JHS
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    JHS polycounter lvl 5
    Make sure you dont export the normals! I had some quite nearly problems too:
    http://www.polycount.com/forum/showthread.php?t=124191

    and found an answer here:
    http://www.polycount.com/forum/showthread.php?t=116474

    it could be a problem that if you export the normals, toolbag, xnormal or udk will not recalculate the tangents and show some strange effects in lighting.
  • Swizzle
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    Swizzle polycounter lvl 11
    CougarJo:

    Offset one half of your mirrored UVs outside the 0-1 UV space and then post a screenshot. That problem usually shows up if you have overlapping mirrored UV islands because of the way Marmoset renders normals.
  • CougarJo
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    CougarJo polycounter lvl 6
    Swizzle : I've found a plugin to offset the uv properly (1 clean unit, not 0.99 by hand, for example) annnnnd IT WORKS!

    You are right, the overlapping was the problem!

    Thanks everyone for the fast answers! :)
  • Swizzle
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    Swizzle polycounter lvl 11
    Sweet. Good to know it worked.
  • s1dK
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    s1dK interpolator
    Hello, is there another way to get nice shading in your normals without adding extra loops ?

    In the left i added extra loop to control the shading in my normal map...and the right one is without and you can see what a ugly shading i have, also where i have uv split i have different smth group. Adding on all your models extra loops i think is to much geo or is no other way. Please someone enlight me.
  • ZacD
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    ZacD interpolator
    If you have a synced workflow (look at the handplane thread) it does not matter how harsh the shading on the normal map looks. The first thing is to make sure you high poly and low poly match as closely as possible. You could get better shading with only adding one extra loop if it really bothers you or you cannot have a synced normal map work flow.
  • s1dK
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    s1dK interpolator
    Thanks zac for your answer, i have a good workflow everything is going fine but when i have this type of surfaces i dont think one edge would make it good enough...because if i add one edge on the right side then i will have a bad gradient between and not a nice solid color.
  • Michael Knubben
    Quack! wrote: »
    Gradations in your low poly like that get translated to your normal map bake in unsynced workflows.
    Bit of a pedantic remark, I know, but I just wanted to point out that this isn't accurate, as I understand it.
    Syncing has nothing to do with whether or not there are gradients in your normalmap,they're there to counteract lowpoly smooth shading interpolation - the only issue being that compression artifacts and tangent basis mismatches can make those problematic.
  • Noors
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    Noors polycounter lvl 11
    I'd say the more the normal map has to compensate the low poly, the more shading issue you will get with an unsynced workflow. And indeed the dds compression (and even 8bit format) is an issue, i wouldn't recommand to have these large gradient on big surfaces for the best result. Depends of the size of the thing in the end, if it worthes to add chamfers, split the uv's, etc...because it adds vertices. Anyway, everything is explained in the 1st post :)
  • Quack!
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    Quack! polycounter lvl 13
    MightyPea wrote: »
    Bit of a pedantic remark, I know, but I just wanted to point out that this isn't accurate, as I understand it.
    Syncing has nothing to do with whether or not there are gradients in your normalmap,they're there to counteract lowpoly smooth shading interpolation - the only issue being that compression artifacts and tangent basis mismatches can make those problematic.

    Oops yea, my wording is off. Gradations like that get baked in all scenarios where the low poly geo creates that gradient. In an un-synced workflow the gradation may cause (severe)issues, less issues happen in synced workflows. Sorry about my bad wording.
  • Michael Knubben
    I wouldn't even have pointed it out if it weren't for the fact this is a thread aimed at teaching people. Wouldn't want it to get picked up by people like 'MAEK ERR'TIN QUADS' has been.
  • Quack!
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    Quack! polycounter lvl 13
    MightyPea wrote: »
    I wouldn't even have pointed it out if it weren't for the fact this is a thread aimed at teaching people. Wouldn't want it to get picked up by people like 'MAEK ERR'TIN QUADS' has been.

    Yep no problem man. Maybe I should go back and fix that so I don't confuse...
  • Jrodan
    Goal: Smooth edges on a low poly cube using a normal map. Very simple.

    SoftEdges.PNG

    Blender
    • Modeled and Unwrapped (High and Low poly. Both smooth shading)
    • Exported as .fbx (also tried .obj) (including normals)
    Xnormal
    • Loaded UnityTangentSpace calculator
    • Baked Normals (in both averaged and "use exported normals")
    Unity3d
    • See results...(What am I missing!?)
    • I get soft edges - but the faces shade very strangely.
    • High and Low poly models are smooth shaded. Unity is importing the smooth low poly model.
    Problem.PNG
    See the weird shading? I am running out of things to try...any ideas?
  • Quack!
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    Quack! polycounter lvl 13
    What does the 2D normal map look like?

    If your FBX version doesn't match the version that xnormal uses, you get bad baking errors.
  • JHS
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    JHS polycounter lvl 5
    you should find the solution in this thread:
    http://www.polycount.com/forum/showthread.php?t=116474

    i got nearly the same problem.
  • NanoTurtle
    Hi there, I'm trying to get to terms with normal baking and I get the feeling there's something fundamental I haven't figured out in regards to smoothing.

    k9X2j65.png

    7ZKVVMi.png

    The cube has six UV islands and six smoothing groups yet there's still a visible seam.

    The second mesh is 2 UV islands and 2 smoothing groups. Where the smoothing groups meet there's a seam while the rest of the mesh smooths properly.

    Is there Anything I have done wrong to cause this or should i use a cage to get rid of these seams ?
  • mAlkAv!An
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    mAlkAv!An polycounter lvl 5
    Yes, you'll need to use a cage.
    Check this wiki entry for an explanation: http://wiki.polycount.com/NormalMap?action=show&redirect=Normal+Map#Working_with_Cages
  • NanoTurtle
    O3rv89d.png

    Even with a cage I can't seem to get it better than this. It's just a low poly cube surrounded by a high poly smoothed cube surrounded by the cage/scaled up low poly.
    There's got to be something I'm missing ...
    Been trying for 2 hours now and my results only seem to be getting worse.
  • mAlkAv!An
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    mAlkAv!An polycounter lvl 5
    There might be something wrong with your cage setup / export settings.
    Do you bake in xNormal, exporting models as .obj from blender?
  • NanoTurtle
    Low poly is a cube with flat shading or smooth with an edge split modifier, doesn't seem to matter. Plenty of room for edge padding.
    High poly is just a smoothed cube around the LP.
    The cage is a scaled up version of the LP.
    They're individually exported as .obj. I don't know the ideal export settings though.(Include edges, smooth groups, Include normals)
    Using the default bucket renderer with 32 pixels of edge padding in Xnormal.
  • mAlkAv!An
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    mAlkAv!An polycounter lvl 5
    I'm using these settings for LP and Cage Meshes for the latest blender builds (this is with an Edge Split Modifier for both):
    exportlpcage01vqux9.png

    For 2.68 and before you can (need to?) also check "Include Normals".
    In case you don't get this working I'd suggest to upload a .blend file so someone else can give it a try.
  • NanoTurtle
    With those settings the bevel looks a bit better but the seam is still there.
    I put a .blend on my dropbox.
    https://www.dropbox.com/s/yh5smavrellamfp/BakingTest.blend
  • mAlkAv!An
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    mAlkAv!An polycounter lvl 5
    Made a quick test and everything worked fine. All I did was moving LP and Cage Mesh to the same location as the HP and adding a triangulate modifier. Then exported with the settings above. http://www.abload.de/img/cubecagebake001rgjyv.jpg
    I wasn't able to compare it with your normal maps because they haven't been packed with the blend file.
  • NanoTurtle
  • mAlkAv!An
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    mAlkAv!An polycounter lvl 5
    Green channel is flipped. You need to bake with X+ Y+ Z+ in xNormal.
  • NanoTurtle
    Getting there, the right edge looks how I want it's just the others that still have a seam in them. (or am I asking too much here ?)

    ktnZVoU.png

    Also, do you know of any way to change blender to Y- ? I do most of my work for cryengine so it would be easier if I could preview my maps in blender without having to do any manual inverting.
  • mAlkAv!An
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    mAlkAv!An polycounter lvl 5
    You need to change the color space from sRGB to Linear for .tif images.

    As for inverting the green channel in blender you can probably use a simple texture node setup to do so.
  • JohnBarnard
    Hello everyone.

    I'm writing a document for my team about best practices for baking normal maps. There are a couple of things I'm still not sure about, I thought I would ask here and see what people think. I've read the wiki and a lot of this thread, but still the answers to these two questions escape me! Here goes:


    1) I understand that placing hard edges can give you cleaner results with less distortion, but I'm wondering why specifically. Is this because of the altered surface normals, or is it just because the normal map doesn't have to work so hard to correct the shading on the low?

    When baking using averaged projection/cage the low poly mesh normals are ignored... so surely the improved normal map can't be because of the surface normals?


    2) Assuming this statement is correct "During the baking process, rays are cast outward from the low poly mesh, and the high poly's surface is sampled at the point where the rays intersect it" How then does a recessed part of the high res mesh get sampled, a part that sits beneath the surface of the low res? At what point do the rays get case the other way?

    I've gotten to a point whereI am am fairly happy with my workflow, and have been asked to share it. I just want to make sure I understand why I'm doing the things that I do. I'd hate to pass on bad information to my peers.

    I'd be really grateful for any advice. :)
  • NanoTurtle
    mAlkAv!An wrote: »
    You need to change the color space from sRGB to Linear for .tif images.

    As for inverting the green channel in blender you can probably use a simple texture node setup to do so.

    Have my babies, it works perfectly now.
  • Hcui
    I painted the grunge on this skateboard wheel in mudbox. I remade it a couple times and made sure there are no seams in Mud but always shows up when rendering with the normal map in Maya.

    Think it's something to do with vectors sharing two UV's which I don't understand. I've tried splitting Uv's, and cutting UV edges - nothing worked.

    Rendered image:
    wheel+problem.jpeg

    Texture map:
    seam_issue_textures.JPG

    Please help, all suggestions appreciated!
  • Farfarer
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    Farfarer Polycount Sponsor
    Trev wrote: »
    1) I understand that placing hard edges can give you cleaner results with less distortion, but I'm wondering why specifically. Is this because of the altered surface normals, or is it just because the normal map doesn't have to work so hard to correct the shading on the low?
    Essentially, it's because the gradient doesn't have to be accounted for as strongly. Where a normal map is that light blue colour (R/G/B:127/127/255) it means that the normal points in exactly the same direction as the interpolated vertex normal at that pixel. So the more of that colour you have, the less the normal map is having to adjust the normal. That's why if you bake a cube with hard edges, you get a mostly blue map back out and if you bake a cube that's all softened, you get some pretty large gradients in your normal map.

    Neither is the best way. So long as your tangent baker/renderer are properly synced, then you should be fine.
    Trev wrote: »
    When baking using averaged projection/cage the low poly mesh normals are ignored... so surely the improved normal map can't be because of the surface normals?
    The normals may be ignored for baking with, which is fine. However, they might also be ignored when it comes to creating the tangent basis, this is bad. The vertex normals form a part of the tangent basis and if the normals used to create it are not the normals from your mesh, you'll get a bad result.

    Trev wrote: »
    2) Assuming this statement is correct "During the baking process, rays are cast outward from the low poly mesh, and the high poly's surface is sampled at the point where the rays intersect it" How then does a recessed part of the high res mesh get sampled, a part that sits beneath the surface of the low res? At what point do the rays get case the other way?
    Technically, the rays are cast inwards, not outwards. The point the ray is cast from is actually projected outwards from the surface along the normal (or the cage, if there is one) and then the ray is fired back down that same path to see if it can hit any high-res geometry. As for beneath the surface, some applications will continue the ray to an infinite distance if there is no high resolution geometry above the low-res surface, some will continue the ray for the same distance it's already travelled, some might double the distance inwards, etc...
  • Wayfray
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    Wayfray polycounter lvl 6
    Hi, how can I get rid of the diagonal seams in the normal map on the right? (On the left is the low poly with cage, with the high poly objects in light grey.)
    http://www.flickr.com/photos/[email protected]/10457954894/

    Should I change the projection cage? I tried changing it, but it didn't have any affect on the diagonal seams.
  • ZuiQuan
    I have a question regarding UDK and normals. EQ states that you don't NEED to introduce hard edges where you have UV splits. And it totally makes sense. If I have a mesh in Marmoset it works like a charm (I only have separate SGs where the separate UV islands are). But with Unreal I run into a problem: when I import the mesh, its vertices running along all the UV shell borders are not only split (which is to be expected), but their normals are no longer unified (facing a bit different directions, resulting in a not very prominent hard edge). The import options are all fine.
    Here is a part of a mesh:
    1) One Mesh, One SG. The seams are where the mesh would be least visible.
    [IMG][/img]pOoZaUG.jpg
    2)The same mesh:
    A) Imported as is into Marmoset. Everything remains the same. All the vertex normals are unified.
    B) Imported as is into UDK. Unreal automatically splits the vertex normals along the UV borders and changes their direction.
    3) And as the expected result we have:
    C)Smooth mesh with a normal map in Marmoset with no seams.
    D) A visible seam in UDK.
    8cXRL1A.jpg

    Syncing the normals by means of Handplane doesn't help, of course, as, essentially, the mesh that was used for normals projection and the final mesh in Engine have different vertex normals along the UV seams as the result of this Unreal behavior.

    The same thing can be observed in Cryengine Sandbox.

    My question is why does this happen? What is the purpose of this automatic normal directions alteration. The vertex split is to be expected, of course (it is always there in the first place), but why change the direction of the normals?

    To solve this I might have to manually introduce hard edges with explicit normals of the split vertices along the UV borders, which is a choire. Especially in Max, where my options are to manually assign SGs or use Edit Normals, which doesn't really have any loop selection options (when you select Normals by Edge). Textools only allows to convert separate shells into separate SGs, it does not introduce any hard edges along ALL the UV edges.
  • MrNinjutsu
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    MrNinjutsu polycounter lvl 8
    have you flipped the green channel of your normal map?
  • ZuiQuan
    have you flipped the green channel of your normal map?
    Of course, baked in Xnormal with Y-. Had I not flipped it the artifacts would not have appeared as a mere seam. There was another mesh, which I rendered with MAX RTT (I needed the Mat IDs) and had exacltly the same thing (as expected). The mesh changes on import - that much is obvious.

    The projection is fine. All the channels are in order. Everything triangulated before bake. Cage is used (though it's a single SG anyway).
    This thing is mentioned in the wiki. It's just that I wanted somebody more tech-savvy than me to explain this engine pecularity and possibly better ways to work with it.

    Same things have happened before (the last post):
    http://www.game-artist.net/forums/support-tech-discussion/13103-normal-seams-unreal.html
  • ZacD
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    ZacD interpolator
    I believe UDK will always split uv seams, so you do need to make those edges hard before you bake, because those edges will be hard in UDK. You can try messing with the "Import Tangents and Explicit Normals" in udk whhen importing the model and see if that helps.
  • ZuiQuan
    so you do need to make those edges hard before you bake
    Yeah, I understand that. If only I could find a quicker way of converting all of the UV seams to hard edges...
    You can try messing with the "Import Tangents and Explicit Normals" in udk whhen importing the model and see if that helps.
    It doesn't, unfortunately. Unreal splits and alters the direction of the normals along the UV seam no matter what.
    Just out of curiosity would still be interesting to know why the Engine does that :)
  • ZacD
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    ZacD interpolator
    When a mesh is actually rendered on the GPU, any UV seam has to been split into 2 separate edges, that's why the seam happens. UDK technically could keep the original vertex normals, but it doesn't, it just reads the mesh and splits it.

    I think TexTools for 3ds Max has a button for that, http://www.renderhjs.net/textools/ if not, there's a script for that in this thread http://www.polycount.com/forum/showthread.php?t=71406
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