Rendering with camera inside Vrayclipper (mesh mode) = very slow

[Vizioen]

Title says it all. I have some plants that would normally render through my windows. So I use a vray clipper to clip them before intersecting the glass. Now when I place my camera inside the mesh that is used to clip the grasses, it renders incredibly slow, when I turn it off, it's fast. Don't know if this is intended.

[yavor.rubenov]

Hello,

What is the shape of your mesh ?

Overall it is expected to be slower. For each traced ray we have to check if it intersects the clipper - first we check the bounding box (which is a very fast check) and only if the ray intersects the bounding box we intersect the actual mesh. When the mesh is smaller most of the rays don't intersect the bounding box so things go quick. In your case when the camera is inside the mesh - every ray intersects the mesh bounding box so it has to do the slower check with the actual geometry. If the actual geometry is complex - things get quite slow.

Best regards,
Yavor

[Vizioen]

It's an L shaped volume, I'm going to make a new test where I optimize the shape a little more (make it smaller and only where the grass should intersect with the glass) so my camera isn't actually 'inside' the mesh shape anymore as well because I think that also has an impact (because the exterior renderings where my camera is outside this mesh, don't take that long. I didn't even bother turning it off because it's not visisble from that POV). I'll report back with the results. It's logic that it is slower but I'm talking about a speed difference of about 5-6 times. Without the clipping the rendering (at 1500px) takes about 15-20 minutes. But with it it's about 2-3 hours. So that's a huge difference.