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Strange Lighting Problem

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    Strange Lighting Problem

    Now that I have a bit of time to get into the editor, I can't seem to figure out what is going on with this lighting.

    There is only one BSP cube that is 2048x2048x64 in size. I apply a simple material to it, and build the lighting. The surface appears to be split up into many faceted squares. I tried changing the lightmap resolution to 2 and then to 512. Both produced similar problems, with varying compile times, and didn't solve it. I have no clue what this is, and forum search + google turns up poor results.

    Thanks for any help, and merry Christmas!

    Try changing the build quality


      Did you read the image? It happens no matter what build quality is set. Even with Lightmass, it is this way.


        didnt really notice that bracketed part, its black text, specially from a almost blind person : P,

        well it seems it can be lightmass scattering detail or somethign like that, i had a similiar problem never got around to it much, try removing lightmass and see how it looks like.


          Uhm, I tried using Lightmass, not using it, low quality, high quality, and everything in between. It's the same result...


          My exact steps are:

          1.) Right click on the left toolbar's "Box" button
          2.) change size to 2048x2048x64
          3.) From the menu bar, I go Brush -> CSG Add
          4.) I enter geometry mode via the left toolbar
          5.) I select the top face of this brush
          6.) I go to the content browser, and drag and drop "M_LT_Base_03" onto the surface of this brush. The material applies.
          7.) I build lighting.

          Boom, surfaces look really messed up for some reason. This seems to have something to do with the lightmap resolution, but going to 2 or 512 does not fix this problem.

          Also, I have tried this is a fresh install of December's build, as well as last month's build. There is no change.


            Are you sure this is strictly lighting? It could be the material is set up to behave that way, since it looks like a specular highlight.

            What does it look like looking at lighting-only?


              Edit: I did exactly the same steps you did and I got it right. Try creating this again in a fresh new level?


                I would check your graphics card drivers and make sure they are up to date with the latest ones available if it is happening on multiple different builds. There should be no issues like that with building lighting that I know of.


                  scampie has helped me on an IRC channel. I guess UE3 by default has a really low lightmap quality for BSP? Setting the quality on the surface to 1.0 fixes this problem. I'm wondering if this is practical, given that the default is 32.0. How much a performance hit would a quality of 1.0 give?

                  He linked me to this page which solved my problem.

                  I also am just upgrading my drivers, so I will see if that makes any difference with default quality lightmaps. Thank you all for your help, and merry Christmas.


                    Setting the lightmap resolution to 1 is usually overkill and will definitely increase memory usage. Whether it is worth it kind of depends on the surface and whether it is a focal point or not.


                      That is what I thought. What is a good lightmap resolution for BSP surfaces? Are static meshes really used that often in maps, over BSP? The last engine I was intimate with was Id Tech 4, which uses BSP far more often than meshes. The brush creation system in Radiant is also far more intuitive than UE3's, no offense The trade off for the other tools is well worth it, of course.


                        Static meshes make up the vast majority of the geometry in levels. BSP is used more in the early stages for blocking out levels for testing and for simple filler geometry sometimes. Open any level that comes with UDK or any game made with UE3 and it should be apparent.


                          Just change the lighting to be fully dynamic rather then static.

                          I set up two examples showing what a dynamic light and a static light both look like after lighting had been rebuilt.



                          Truth be told though dynamic lighting isn't worth it unless absolutely needed for a specific area or scene, while it does appear to look neater on surfaces, and more detailed, it doesn't have the glorious global illumination effects you gain with static lighting which honestly is a much bigger plus. Dynamic lighting is also as everyone would of probably guessed more performance heavy.

                          With that said, sure you could use both dynamic and static lighting to get the best of both worlds, but in the end for a scene like this you will always get that patchy appearance on a very blank map with very bland materials if you use static shadowing. Add more detail to your level with more variety in materials and you will see how static lighting with lightmass is much more appealing then dynamic lighting and shadows.

                          However I did see a thread a few months ago about removing lightmap compression via the lightmass.ini file which I suppose got rid of the patch appearance which you would normally get on maps like this with static lighting. I would bet though without any type of lightmap compression, your map file size must increase drastically.

                          Hope this helps.


                            I am well familiar with the difference of dynamic and static lighting The last time I did level design, though, was for Doom 3. BSP is pretty much 90% of all geometry in such levels. It is so important that they decided to write all brushes in the format of intersecting surfaces w/ a surface normal instead of defining individual vertices for each polygon. Dynamic lighting is also more expensive when used on a larger scale, so I wouldn't recommend using such as a primary light source at all. It is one of the reasons why CryEngine 3 gets terrible performance on just about every system - the pixel shaders they use just totally rape whatever it comes in contact with.

                            Thanks for the help, it is appreciated. I understand that lightmaps are stored in the UVs for static meshes, so I assumed such things wouldn't happen when using them. The fact that BSP lighting is so terrible is partially deceiving, because I would have assumed the fact an engine uses BSP at all is because it is fairly important for precomputed visibility (it is very important in Id's engines.)

                            Merry Christmas to all


                              Technically speaking, UE's geometry is defined as CSG. BSP is a spatial partitioning system (for the purposes of optimisation) and not strictly directly related, although it's possible UE applies BSP when defining geometrical operations in CSG.

                              I do get a bit bugged when people refer to world geometry as 'BSP' - because it isn't

                              ...does Unreal actually use BSP, or does it use some other form of partitioning?