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splok · 07-02-2008, 09:37 PM

Different editors handle optimization in their own ways, but in general, on a reasonably sized level, you aren't likely to run into many geometry based performance issues. The things that eat your performance most quickly will probably be particle effects and dynamic lighting. Although using tons of models without proper occlusion can cause problems as well. For example, the dino level was really big and had literally hundreds of tree models. Performance on the initial pass of that level was horrible because WAY more polys were being drawn than UT2k4 was happy about, so we had to add a lot of elevation variation (hills, plateaus, and such) similar to UT's Onslaught with occluders inside to keep the visible polys within reasonable limits.

As far as specifically breaking large bsp up, there should be a command in whatever editor you're using to show the cuts that the editor is making in your level. It makes them for optimization purposes automatically, but your geometry construction can inadvertently make them much more complicated than need be. That's handled differently per editor too. Source makes a cut not matter what every 1240 on the x and y axis i believe, but makes no automatic cuts at all on the z axis, requiring you to use a hint brush to force a vertical cut if you want one. Another concern might be lighting. In UT2k4, light is averaged across bsp verts, so if you have a really large piece of bsp, it may not light properly. Sometimes you need to make cuts to get the lighting granular enough to get the effect you are looking for.

Basically, I would say don't worry about it too much until it starts creating noticeable problems (just keep the fps meter up and pay attention for any wonkiness). Of course, if you want to get in the habit of using the cleanest technique possible, that great too. You'll just need to read up on optimization for whatever editor you're working in. I'll try and toss out some suggestions for any questions you might have (of course, I'm no expert, so take that for whatever it's worth), but much of it is going to be editor specific.

07-02-2008, 09:37 PM	#21 (permalink)
splok Registered User Join Date: Apr 2002 Location: Oslo Posts: 527 +2 Internets	Different editors handle optimization in their own ways, but in general, on a reasonably sized level, you aren't likely to run into many geometry based performance issues. The things that eat your performance most quickly will probably be particle effects and dynamic lighting. Although using tons of models without proper occlusion can cause problems as well. For example, the dino level was really big and had literally hundreds of tree models. Performance on the initial pass of that level was horrible because WAY more polys were being drawn than UT2k4 was happy about, so we had to add a lot of elevation variation (hills, plateaus, and such) similar to UT's Onslaught with occluders inside to keep the visible polys within reasonable limits. As far as specifically breaking large bsp up, there should be a command in whatever editor you're using to show the cuts that the editor is making in your level. It makes them for optimization purposes automatically, but your geometry construction can inadvertently make them much more complicated than need be. That's handled differently per editor too. Source makes a cut not matter what every 1240 on the x and y axis i believe, but makes no automatic cuts at all on the z axis, requiring you to use a hint brush to force a vertical cut if you want one. Another concern might be lighting. In UT2k4, light is averaged across bsp verts, so if you have a really large piece of bsp, it may not light properly. Sometimes you need to make cuts to get the lighting granular enough to get the effect you are looking for. Basically, I would say don't worry about it too much until it starts creating noticeable problems (just keep the fps meter up and pay attention for any wonkiness). Of course, if you want to get in the habit of using the cleanest technique possible, that great too. You'll just need to read up on optimization for whatever editor you're working in. I'll try and toss out some suggestions for any questions you might have (of course, I'm no expert, so take that for whatever it's worth), but much of it is going to be editor specific.