How costly is baked lighting on performance?
I was under the impression that when static lighting is baked, it uses up the same amount of performance each time, regardless of the settings, since it isn't baked in realtime. However, when using some overkill values in the BaseLightmass.ini, I noticed a 30-40 FPS drop after the lighting was built (same scene as I had with different tests- used to run at 120 FPS, but with the different baking settings it now runs at 80-90 FPS. Is it wise to find a good balance between high settings and performance, or are there any things that would particularly affect performance negatively when baking static lighting? I would like the highest visual quality while having decent performance (at least 60 FPS). I believe I also changed the indirect lighting quality and the static lighting level scale. Finally, does increasing the size of lightmaps greatly decrease performance? (Had all shadow lightmaps to 4096, and most geometry at higher levels than necessary)
Things that increase memory (which can reduce performance especially if nearing the limit of the machine) uncompressed lightmaps higher resolution lightmaps * smaller static lighting level scale
Things that increase performance cost The more stationary lights there are on your screen, and especially how many dynamic objects they affect Presence of a stationary skylight adds a bit * smaller static lighting level scale will generate more volume lighting samples and increase the interpolation cost for dynamic objects
Otherwise, baked lighting performance is fairly independent of different settings.
As always, use profiling tools, don't just guess at performance and memory. 'profilegpu' for GPU performance.
answered Feb 23 '15 at 11:26 PM
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