OTOY Forums

I have a question about portals. The manual states that, for instance, when using portals, every window opening in a room must have a portal in front of it. It won't work if just one window is covered. My question is that what classifies as an "opening"? In other words, does the mesh of the room need to be water tight, so that a slight gap anywhere in a sloppy mesh would also need to be covered with a portal? Those gaps are, after all, "openings" to the outside environment. How would Octane distinguish between an important opening, such as a window, from an unimportant opening such as a gap somewhere in the mesh of the room? Or an intermediate opening like a golfball sized hole in a wall?

I bet it works as a way to let the raytracing engine know where a ray must be sampled more. So if a ray hits the portal, it knows to cast more ray samples from that position on the portal, into the room... instead of the just 1 ray.

But that's my guess.

I understand that part of it, but the confusing part is that the manual states that ALL openings must be covered with a portal, not just one of them. So if a room has 4 windows, one on each wall, all of them must be covered, or the portal thing doesn't work. So if the room mesh is sloppy and not water-tight, technically little gaps in the mesh classify as openings that must also be covered along with all the windows.