CULPRIT FOUND! 2fort_water_expensive is a no-no! I'm working on a King of the Hill map named Mill. I've recently run into an issue with the HDR that I can't pin down, but I can pinpoint the version on which it started. I've brought this to 6 other mappers and they've never seen anything like it. I'm starting to lose it over this! THE EVIDENCE http://i.imgur.com/e0vB6.jpg http://i.imgur.com/3bvxM.jpg http://i.imgur.com/HZpIG.jpg http://i.imgur.com/IxXya.jpg Just flip between those really quickly, thats exactly whats happening. Alternatively if you've downloaded the b1 version and would like to see them, here are some getpos: Here are some getpos that show specifically where I'm getting them. The blue spawn spot and the ledge. Strafing between those two spots causes it. Aiming at the white brick building. Moving foreward in the mill attic. Double alternatively, watch this video FLOOR_MASTER graciously made for me: http://dl.dropbox.com/u/53150/mill-flicker.mp4 WHAT I KNOW Does not happen when HDR isn't on in the compile, and when HDR is disabled in game. Happens on both Fast and Normal compiles. Haven't tried final compiling. Shows up for everyone in a multiplayer game. Its definately switching between the LDR and HDR settings for ambience and brightness in the light_environment. I've changed the values and the change is consistent with it. The spots its happening in is consistent, but I can't figure out why its happening there. The tonemap and light_environment settings are from arena_lumberyard. I've tested with the tonemap and light_environment settings of Upward, still causing it. Removing all the cubemaps from the afflicted maps does not fix the issue. Flickering happens on both ATI and Nvidia cards. Might be in different spots though. No errors in the compile, I've verified this with the Interlopers checker. As an extension: I've recompiled both versions of the maps when it showed up. It consistently happens on the one where it showed up and doesn't happen on the one it didn't. I've cleared all both versions (t6 and t7) problem's list. Map Properties are the same for both maps. The version that it does not happen on and the version it does happen on: same light_environment settings. same env_tonemap_global settings. same env_cubemap locations and build processes. rest of the point entities (water_lod, shadow_control, env_fog_controller, etc) have the same settings. The difference in the two maps is some instances and some new detailing that is all func_detailed. Heres the map I took the screenshots on: http://dl.dropbox.com/u/53150/koth_mill_b1.rar The version where it DOESN'T HAPPEN: http://dl.dropbox.com/u/53150/koth_mill_t6.rar The version where it STARTED: http://dl.dropbox.com/u/53150/koth_mill_t7.rar Please ignore the performance issues, I have them fixed in a new compile and will make a thread about it when I get that version done. I can circumvent the issue for now by not compiling HDR or setting the LDR and HDR to the same values, but I'm going to have to address it eventually. I am doing this irl: Someone point out the elephant in the room I'm missing please!