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total noob, my first box doesn't seem to be receiving shadows

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    total noob, my first box doesn't seem to be receiving shadows

    No need to post a screen grab. I just imported a box, with textures from max. If I place a default brush box infront of it, it doesn't receive shadows. Casts ok though.

    Any ideas?

    #2
    Did you build lighting? If you used a box primitive from Max and didn't adjust the UV's then the UV's aren't correct for lighting.

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      #3
      If it receives shadows before a light bake while its still a dynamic preview but then messes up after you bake light then it does sound like a lightmap issue.

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        #4
        Yeah, here are two images. Top is pre light calculations and bottom is post. Any ideas how I fix this? the box is imported from a collapsed mesh with UVs but I can't be too sure if I used reset x-form (if that makes a diff).

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          #5
          You have to make a second UV set that has unique coordinates for each face. So no overlapping faces. Then lightmass will use those UVs when it bakes the lightmap texture.

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            #6
            Ok. I'm not sure what you mean though, or what method I use to do that?

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              #7
              You can either generate a new set of UV's in 3ds Max, on a second UV channel where everything is flattened out and within the 1x1 space and not overlapping. Or you can open it up in UDK and use the Generate Lightmap UV's tool in there which will do it automatically.

              After that, change your lightmap resolution, by default it's 32 (32x32) and it's probably too small making the shadows so blurry that you can't see them.

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                #8
                http://udn.epicgames.com/Three/LightMapUnwrapping.html

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                  #9
                  Thanks for the tips guys. Seems very complicated. Will read over all that.

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                    #10
                    Very easy actually in MAX. Apply a Unwrap UVW mod to the box, set to map channel 2, for that simple box just open the UV editor, select mapping>flatten mapping. This will place all your faces flat within the texture space without overlapping. This is the simplest unwrap. It gets complicated from here.
                    Export, reimport in UDK and bake again
                    That's a good, easy place to start. You will need to understand UV channels in detail if you are making custom assets. Do a google search on UV Unwrap in 3DS Max (or whatever modeling package you may be using) and do as many tutorials as you can stand.
                    For my workflow, I ALWAYS have at least 1 UV channel for texture mapping and 1 for lightmap.

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                      #11
                      I use max and did a UVW unwrap on it. But didn't know it needed two. And I'm not familiar with uv channels... and needing multiple ones. Say, why would you need more than one for texture mapping? Could you maybe give an example. I thought you just unwrap and that's it? thanks.

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                        #12
                        Well, in this particular case, you need one set of UV's for the texture map (diffuse, etc). Typically, that goes on UVW channel 1 in Max. In the UDK, lightmass needs a UV channel to bake the lightmaps to. This channel MUST be within the texture space and MUST NOT have overlapping faces. Otherwise, you get really funky light bakes.
                        In our workflow, we call the channels the diffuse channel and the lightmap channel. You see, the diffuse channel can have overlapping faces and be well outside the bounds of the texture space (tiled textures for example), but the lightmap can't. Sometimes, when we use unwrapped textures, we use the same UV coordinates for both channels. In your box example, a (I'm guessing here) UVW Map was applied to the box with box mapping selected (or you just used the default mapping for the box, which is a box map). If you look at that channel in the UV editor, you'll see all faces stacked on each other. Good for the diffuse map, bad for lightmap.
                        By the way, in the UDK, map channel 2 is used by default for the lightmap. Now, don't get confused here! UDK starts numbering at 0, where Max starts numbering at 1. So in Max, you have UVW channel 1 and in UDK that's UVW channel 0. So Max 1= UDK 0, Max 2= UDK 1. Make sense?

                        On a side note, multiple UVW channels can be a really cool thing! You can use one channel for a diffuse map and a second channel for some cool overlayed effect and you can layer these channels with different UVW coordinates for some really fun stuff! It can get real complicated, so stick with the diffuse channel and lightmap channels until you get that perfected.

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