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My unwraping sucks, not sure what im doing wrong.

polycounter lvl 12
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biofrost polycounter lvl 12
I get the basics of unwrapping but it seems I keep making mistakes but I'm not quite sure what they are. I keep getting stretching in parts and overall just not sure if I'm doing this right. So here is some textures and Maya scene file and obj for users not using Maya. Any help is greatly appreciated.

Maya file: http://dl.dropbox.com/u/37279376/PolycountFiles/Quake4Cratev3.mb
Obj: http://dl.dropbox.com/u/37279376/PolycountFiles/Crate.obj
Uvmap: http://dl.dropbox.com/u/37279376/PolycountFiles/uvmap.bmp
Diffuse: http://dl.dropbox.com/u/37279376/PolycountFiles/CrateDiffuse.tga
Normal: http://dl.dropbox.com/u/37279376/PolycountFiles/CrateNormal.tga

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  • Ott
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    Ott polycounter lvl 13
    .JPGs preferred....
  • EarthQuake
    please post some jpeg images to show the problem, not everyone wants to/has time to download your maya file and textures, or has maya installed etc.
  • biofrost
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    biofrost polycounter lvl 12
    Sorry about that, here are the jpgs.
    cratea.jpg
    cratediffusecopy.jpg
    uvmaph.jpg
  • Sage
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    Sage polycounter lvl 19
    Put a grid texture on your model to find out which uv islands need to be fixed so there is no stretching. UVs sometimes need to be modified as you texture things if they are not giving you the results you need. This becomes easier the more you do it.

    Also it's really hard to see the stretching on your model since the image is kind of small. You probably want to put this in the P&P section to get more feedback. Post more shots of your model there and indicate the problems you are having.
  • Ace-Angel
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    Ace-Angel polycounter lvl 12
    Can't say really, could you upload a larger picture of the render? Something around 1K big, because I can't really tell what's stretching.
  • tharle
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    tharle polycounter lvl 9
    doesnt look too bad imo, i did notice that the part with the gun is stretched in the up-down direction whereas on the model it's more longwise. try to keep faces the same proportion in the uv space as they are in model space.

    are you using a checkerboard texture when you're doing your unwrapping? theres a few standard coloured ones like these, or even just a basic maya checker pattern, which should make it easier to see where you're getting stretching.

    theres a fair bit of wasted space too - uving is a bit of a dark art as you want to keep face proportions right but also use all your space and its basically just a balance between the two. a lot of it just comes with practice though.

    if you've havent already try playing with maya's relax and smooth uv tools - they try and get the uv's back into world space proportions and you can do things like pin edges or just smooth one direction which can be really useful.

    hope that helps!
  • biofrost
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    biofrost polycounter lvl 12
    Yeah the gun was a big issue, I had it on the front also and it was stretching. It seems is is from not keeping some of the uv's the same proportion, I would scale some in the x axis but not the y. So pretty much I should try and scale everything uniformly for the best results unless I just the realx and smooth tools.

    Thanks for the checkerboard idea, I plan on doing that with all my models now!
  • Quack!
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    Quack! polycounter lvl 17
    Always scale uniformly after you have relaxed your uvs. Apply a checker material to your object and scale the uvs in the editor and watch what happens to the checkers on your model. This will show you why.
  • Fingus
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    Fingus polycounter lvl 11
    Your UV's look decent, although you have some squashing and stretching in some places. Maya has a surprisingly competent unfolding tool. Shift + rightclick down in the UV editor to get to it. I can't remember where it is in the menu as I'm too used to marking menus. You can also try out Roadkill. http://www.pullin-shapes.co.uk/page8.htm

    A useful trick to get everything to have the same scale is to use the Layout function, go into the option box and set Prescale to World. That will move and pack your shells and scale them all to the relative size they have on your model. Just don't rely on it to pack your UV's for you as it kinda sucks at that.

    By the way your packing needs a lot of work. You have tons of wasted space. You can pack your shells much tighter than that. The top left corner is a good start, try to get that density across the rest of your map.
  • biofrost
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    biofrost polycounter lvl 12
    Thanks everyone for all the advice, I feel this uvmap is much better packed and should have little to no stretching. uvmapbmp.jpg
  • Quack!
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    Quack! polycounter lvl 17
    You are going to get terrible stretching with the main part of your crate by the looks of it. Are you applying a checker map while unwrapping?

    wrong.jpg
  • biofrost
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    biofrost polycounter lvl 12
    Yeah, this is what it looks like with the current unwrap. No stretching from what I can tell but ill go ahead and change it just to be on the safe side.
    stretching.jpg
    EDIT:
    I can see the difference now, here is a slightly modified version
    stretching2.jpg
    uvmap.jpg
  • Will Faucher
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    Will Faucher polycounter lvl 12
    Your UV's have a TERRIBLE pixel ratio. Some shells are too big, some are too small. You want ALL your checker squares to be the same size, and... well... square.
  • Martin Henriksson
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    Martin Henriksson polycounter lvl 9
    If you select all of your UV islands and then enter this into the mel box it will automatically scale all your island to the same pixel density:

    unfold -i 0 -ss 8 -gb 0 -gmb 0.5 -pub 0 -ps 0 -oa 0 -us on -s 0.2;
  • tekmatic
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    tekmatic polycounter lvl 11
    @Martin: That sound very interesting, but exactly is happening? What are each Mel command really doing? I am a little lost!:poly141:
  • Ace-Angel
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    Ace-Angel polycounter lvl 12
    The first one is dividing by zero on an ipad, the second is scattering by 8, and Great Britain divides it again by 0 one more time.

    After that General Motors Buys half the stock from the Pubs at 0 shillings per PSi, hence negating the value in the market.

    After that all, it multiplies by Africa, and the number of Overseas companies which don't mine diamonds, reverts back to US currency, and minus that by the South America's value cost for Ethanol.

    And voila, normalized map!

    (PS: I'm just kidding).
  • Martin Henriksson
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    Martin Henriksson polycounter lvl 9
    tekmatic wrote: »
    @Martin: That sound very interesting, but exactly is happening? What are each Mel command really doing? I am a little lost!:poly141:

    Tbh i dont know, its just a unfold with 0 iterations, the unfold tool only allows you to set it to 1 so you have to enter that value manually. So the different commands are the other values that you can change in the unfold tool, they are all set to standard in that line.
  • biofrost
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    biofrost polycounter lvl 12
    @Martin: Thank you that script worked wonders, I am in the process of packing everything back in now.

    Man I can not thank you guys enough, quite honestly since I found out about polycount I have learned more here than the 3 years so far of college.

    Edit: Here we go, the new unwrap! I could pack it alittle bit tighter but I think I am getting the right idea..I hope.
    uvmapf.jpg
    fixedhopefully.jpg
    fixedhopefully2.jpgfixedhopefully3.jpg
  • tekmatic
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    tekmatic polycounter lvl 11
    Yeah I think these UVs are packed a lot better than before. But if you look at the image you posted last with the top down view of the model, there seems to be a little stretching of the checkered map (the boxes look a bit on the rectangle side as compared to other parts of the model.

    Anyone else see that? But you are on the right track.:thumbup:

    @Ace-Angel.....dude that explanation got me to down few aspirin pills....damn that was complex LOL
  • Martin Henriksson
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    Martin Henriksson polycounter lvl 9
    right now the biggest problem with your model is the bad shading you have on several parts of it. You see those black spots? It can be many different things but most likely you have either a soft normal on a 90 degree edge or you have double faces / unwelded vertices in those spots.
  • biofrost
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    biofrost polycounter lvl 12
    Most likely a soft normal because right now the entire thing is softened. I was under the inpression you should always soften the normals or is it a model by model basis when you should or should not?
  • Martin Henriksson
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    Martin Henriksson polycounter lvl 9
    Yes its from model to model and how build it. If you are going to bake a normal map from a highpoly different rules will apply then if its just a lowpoly. You should definately make those edges hard on that model imo or bevel the edges.
  • biofrost
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    biofrost polycounter lvl 12
    I may bevel because I am going to be baking from a high poly model.
  • Martin Henriksson
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    Martin Henriksson polycounter lvl 9
    q4crate.jpg

    This is the same texture/model that you posted in your first post but with fixed normals. The normal map that you posted was pretty broken and unusable so if you intend to go that route then yeah you definately need to rebake after you have fixed the shading issues.
  • biofrost
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    biofrost polycounter lvl 12
    Thank you everyone for the help! I have re baked it and unless anything looks wrong with the bake am taking this back to pimping and previews where I will be attempting to texture this bad boy. screenshot0copy.jpg
  • Visceral
    From this angle it looks really good! Nice improvements here.
  • Will Faucher
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    Will Faucher polycounter lvl 12
    If you select all of your UV islands and then enter this into the mel box it will automatically scale all your island to the same pixel density:

    unfold -i 0 -ss 8 -gb 0 -gmb 0.5 -pub 0 -ps 0 -oa 0 -us on -s 0.2;

    Quick question. Is there a normalize option such as this in Max? I know it's simple in Maya, but I have no idea how to do so in max.
  • haiddasalami
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    haiddasalami polycounter lvl 14
    Prophecies wrote: »
    Quick question. Is there a normalize option such as this in Max? I know it's simple in Maya, but I have no idea how to do so in max.

    Not too in depth with the max interface but MoP wrote a script

    http://www.polycount.com/forum/showthread.php?t=52415
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