Ok so I have come across an insanely bizzare lighting problem. I've got a custom prop made by yours truely and i have several copies of it one after the other with a teensy tiny bit of overlap between them but nothing that should cause problems (and indeed when moved to counter the overlap by ~3 units there is no change) Of course I'm running with -staticproplighting and there is evidence of this working on all of the props in question. here is the problem ingame: As you can see one prop is lit nicely and the one directly next to it is pitch black even though as the brush placed next to them for reference there is clearly enough light in that area for it to be well lit. To further show that something is wrong ingame and not in hammer the raytraced lighting previews show that the prop should be recieving enough light. As shown here: Which clearly shows (almost no bounce lighting) that the lighting on each is pretty even. Since i know the first poster will demand a compile log even though i can asure you all there is nothing anomolous in it, here it is anyhow - Here, click me. And since i know someone will say it, i'll restate it: This is taken with -staticproplighting added to the compile parameters. The prop's origin isnt even in any geometry anyhow, it should be directly in the light. No leak, compiled with cordon.