Mike Snowdon · VFX DirectorThis is interesting because the particles on their own, there's no real concept of that. If I just place a big smoke effect in a room, nothing's going to stop that particle as it is from just going outside the room, and certainly it's not going to react to the ceiling and crawl along it. Having said that, if we're clever about it... and again, for fire, we are going to be wanting to do this. Try not to commit overly to some of these things. But for fire, we want smoke crawling along ceilings eventually. That's something that we aspire to be able to do. That's just how you mark it up. So maybe, again, we use signed distance fields a lot; maybe we have a similar kind of setup there. I know we've actually played around with that in some of our fire work so far. Vis areas, actual screen space collision on certain effects. It depends on what the effect is, I guess. But again, it depends what the game needs and what design are asking for, what art are asking for. We can absolutely make it do that, but it might be more complicated to get it to look visually right.