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    Dynamic Shadow Problem

    My problem is that dynamic shadows don't work properly and I refuse to belive that this problem does not have a fix. Games that use Unreal Engine 3 like borderlands and transformers war for cybertron all use dynamic shadows and this problem doesn't arise in those games I am not sure if I will be able to find a fix in the forums I might have to go somewhere else but here is a picture of my problem.



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    The shadow goes through other objects and with the games I mentioned along with other demos with the UDK I have seen use dynamic shadows and don't have this problem I am really getting frustrated at this and am hoping for a fix because my time and effort into this problem has gotten me no where.

    #2
    Use dominant lights.

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      #3
      Using dominant lights will fix the shadow but here's the reason for the shadow problem, which can also be fixed without dominant lights. The reason is that by default all lights, accept for dominant lights, use the modulated shadow type. This shadow is essentially a "fake" shadow not actually being casted by the light source. The shadow does not get blocked by anything and if you had overlapping shadows they just get multiplied together. You can see one shadow crossing another, which of course is not a normal shadow behavior. It's really a method of getting dynamic shadows on dynamic objects from static lighting.

      To get real dynamic shadows you can either use movable lights or dominant lights. The difference is that movable lights is completely dynamic and you have to still switch the shadow mode to "normal" to get proper shadows. Dominant lights blend a static and dynamic shadow seamlessly and by default will just work correctly. You also get a fully dynamic dominant light which is of course fully dynamic.

      It is also worth knowing that you can't use multiple dominant lights crossing over each other. with directional lights the editor will actually prevent you from placing more than one but with point or spot lights you can place any amount and you should be aware of problems when placing two dominant lights that intersect, even just a tiny amount will cause problems. Basically what it is, they can't touch the same mesh or polygons by any amount. It will cause some problems with your shadows.

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        #4
        Only on consoles though obihb, from what I've heard. Sadly we don't have to worry about that...

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          #5
          Yes coffeeGrunt that is true it only causes problems on Consoles but it reduces FPS on PC's as well.
          An Thanks for all the help.

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            #6
            Not really sure why consoles are mentioned here but I'm talking about the UDK which runs on PC and all my comments about the lights are based on what happens inside the UDK currently on the PC.

            As far as I know the UE3 does basically the same stuff on both console and PC and it just depends on how you use it and what gets you the frame rate you need. That's why there's a choice of various ways to do things. But still, my comments are directly based on UDK features which may or may not be the same as any previous or recent console version of the UE3 depending on which game you compare it to. I am not doing any comparisons though, just giving some info on what the UDK currently does with regards to lights.

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              #7
              It seems that the dynamic shadows don't use global illumination. Or I am using it incorrectly any help?

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                #8
                Dynamic SHADOW doesn't use global illumination. Shadowing and GI are separate. Even though one may effect the other. And of course you can use GI/Lightmass with dynamic shadow.

                Lighting is more of art than science so there's no hard rule. Everyone has different method so you need to experiment. But you will need to learn some basics. Everything I know I learned from 3DBuzz Tutorials and UDN. You can do the same.

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                  #9
                  I watched everything except like 2 vids of the lighting lol I will go do that to see what I can do.

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