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    Little rant

    Guys, before somebody accuses me of:
    a) being lazy
    b) not understanding how lightmaps, lightmass work
    c) criticizing UDK

    In reply to the above:

    a) I'm not lazy, I work on average 10 hours per day/7 days a week (yes seven days a week)
    b) I've read lots and lots documentation about lightmaps, I've watched tutorials etc. I believe my level of understanding of them is good.
    c) Love it!

    Ok, now to the rant part:
    [rant begin]
    What really frustrates me is the fact that not only I have to unwrap my mesh for texturing which I'm OK with and I have no objections to do so, but second unwrap for lightmap?! I mean seriously, sometimes I'm spending more time on the second unwrap than on first and why? Because I'm doing something which engine should do and is much better of doing so. This is typical job for a machine! And unreal engine (in UDK) already does it! When you put object on the map, the object is correctly lit based on a lights and shape of this object. The engine figured out (very correctly/precisely!) how the shades should look like and where they should be. But no! Instead of concentrating on tasks which require human attention I'm doing lightmaps! I'm forced to figure out which faces are facing same (similar) angle, how the light will affect them etc etc. This is simply wrong! This is counterproductive and I hope that lightmaps will be removed from next gen of UDK.
    [/rant end]
    Regards
    smallB

    #2
    Static meshes uses static lightning with or without lightmaps.
    Dynamic meshes (KActors, KAssets, Skeletals and so on) uses dynamic lightning, and not need lightmaps.

    If you don't want to use lightmaps, in mesh, set it's resolution to 0, and you will get simple vertex lightning.
    If you use lightmaps, statics needs some unique unwrapped UVs for baking lightmaps on it.

    Lightmap UVs needs to be unwrapped uniquely, without any overlapping of UV shells.

    If your 1st (main) UV channel unwrapped in that way, in mesh set lightmap UV channel to 0, and you don't need any other UVs.
    If on your 1st (main) UV channel UV shells overlapped, or mirrored, or something else, you need to create 2nd UV channel with unique unwrapping, and in mesh set lightmap UV channel to 1.

    I don't know why you need some additional time for unwrapping 2nd channel, because you can simply copy UVs from 1st channel on 2nd channel and layout it automatically.

    Or you can generate 2nd UV channel in Unreal Editor - http://udn.epicgames.com/Three/Stati...Guide.html#UVs
    It's weird, but can save your time.

    Comment


      #3
      Originally posted by smallB View Post
      I mean seriously, sometimes I'm spending more time on the second unwrap than on first and why?
      If you are spending a lot of time on the lightmap UVs you are doing a lot of uneccessary things.
      Unlike the texture UV, it doesn't need to be optimized for texturing and a lot of simple semi-automatic solutions will work just fine.

      Quickest solution is to simply repack your texture's UVs or just move things that are overlapping, and you are done.

      No need faffing about with angles and such as you are talking about.

      A lot of people seem to complain about having to make lightmap UVs, but it literally takes me seconds.

      Edit: Basically what redbox said.

      Comment


        #4
        Hi redbox and Graylord,
        Thanks for your answers! Generally I'd encountered problems with light maps on rounded shapes (bleeding, wrong shadowing), even though I've "checked every box" on how to do correct light maps. Anyway, the hint by redbox of making resolution to 0 and going with vertex lighting is fantastic!
        Thanks again guys.
        Regards
        smallB

        Comment


          #5
          Originally posted by smallB View Post
          Hi redbox and Graylord,
          Thanks for your answers! Generally I'd encountered problems with light maps on rounded shapes (bleeding, wrong shadowing), even though I've "checked every box" on how to do correct light maps. Anyway, the hint by redbox of making resolution to 0 and going with vertex lighting is fantastic!
          Thanks again guys.
          Regards
          smallB
          It produces bad visual results with shading, and be careful - it's good only for meshes with small number of vertices, because it can cause performance troubles.

          Comment


            #6
            By the way, UDK does have a tool for automatically creating lightmap UV's. And if you're using something like 3ds Max, you can do an automatic unwrap in there as well. They aren't as good as doing it manually, but if you don't want to mess with it that's an option.

            Comment


              #7
              Hi again,
              Yes, I am aware of both UDK being able to produce unwrap and 3dMax automatic tool (which in fairness is quite OK) but non the less, I've used everything I've got and till today before I've got reply from redbox and Graylord I had terrible problems with a car I'm doing. Anyway, thank all you guys for your help.
              Regards
              smallB

              Comment


                #8
                Why do you need lightmapping for a car? Is it going to be a static prop in the scene? Because if not, you don't need to worry about lightmaps at all.

                Comment


                  #9
                  I think you can divide your car on few main sewed parts, like main body, doors, bottom part, wheels, interior and sittings.
                  and avoid any serious lightmap seams.

                  Comment


                    #10
                    Hi guys,
                    In the link below you can see what's the problem I've had while trying to make that car (it is static prop on the scene, as you can see it is divided into appropriate parts). The point is that doesn't matter how I've unwrapped it for ligthmaps the results were poor, poor, poor. I've tried to change the res, I've tried hundreds of different UV layouts and what not, and this did not help. If not for redbox's advice on vertex lighting I really don't know what I would do. Thanks again redbox!

                    http://www.mediafire.com/?21nfd90mwv...hudx6lf8zf17qg

                    Regards
                    smallB

                    Comment


                      #11
                      My guess is this--the car might have too high of a poly count, the frame around the window isn't really necessary and it's a detail you could put into a normal map. The issue is that since the frame is so thin, it looks like it's being separated out from the rest of the mesh in the lightmap, and then it's getting bleeding over the edges which is what makes it look bad. There's a way to unwrap that though that would get rid of that issue. The main deal with unwrapping is to have as few seams as possible, and for the seams that you do have, put them in unimportant places if you can. For instance on the door of the car you can flatten out the entire surface by putting a seam around the door and then another seam around the inside of the window, that should make the door and the frame flatten out correctly and you won't get that weird shadow around the frame due to bleeding.
                      The only other way to improve the quality if you get bleeding in areas is to increase the lightmap resolution.

                      Comment


                        #12
                        it looks loke you have very high res for lightmap.
                        try to set something around 128 for whole car.

                        Comment


                          #13
                          also - do you have ambient occlusion baking in lightmass?

                          Comment


                            #14
                            @darthviper believe me, I did all of what you've suggested and more - nothing helped. I've tried different unwraps method hundreds times over, with and without seams, like you've suggested I've placed seams in those places and nothing, nothing, nothing... What was very interesting though, that if I increased lightmap res to let's say 1024 it look worse than with 512. As I've said, if not for @redbox I would still banging my head on the table, wall and floor
                            But if you want to try out your skills I can send you this door and back of the cabin and you can try if you can unwrap lightmap for it so it looks good WHILE SHADED (not directed into light source). Let me know if you interested, and I'd love you to do it so I can learn something again.
                            Regards
                            smallB

                            Comment


                              #15
                              @redbox, you mean ambient occlusion set to true in world settings?

                              Comment

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