Calculating IM with displacement

[fAEkE]

I'm using displacement for a couple of towels in bathroom scene and the IM takes forever to calculate. I put it on render during the weekend and prepass 2 was supposed to take 175 hours :/..

it's a 5000px render, nothing special with the scene. Vray sun/sky and a couple of vray lights. 2D displacement with 1024 resolution and 4 precision. IM settings something similar to HIGH preset -2/-4 and 150/50. Secondary is LC with 1500 subdivs.

Anyone got an idea about what might be wrong? I use displacement in a couple of other scenes and I got no problems there.

And Vlado, please implement a setting for vray displacement that disables GI calculation for displacement, that would be awesome! Just make it calculate the geometry as without displacement, it almost always works just as good for me. The problem is that now I need to calculate the IM, save it, and then render the image.

[Deflaminis]

Maybe it's changed in vray 2, but I've seen much faster renders with the 3d displacement as opposed to the 2d displacement.

How many levels of turbosmooth can affect things from tests I've done. So if your mesh is really subdivided in the first place it helps the render times quite a bit. Maybe your other meshes were smoothed or dense, and your current one is not so Vray has to do the subdivisions instead of max.

[fAEkE]

Hmm, I always go with 2D since 3D usually takes forever to render. And I always use a subdiv modifier before the vraydisplacement modifier. I don't think that is the problem, the quality of the displacement is fine.

I have tried it some more now in two different scenes and something is very strange with displacement and IM. In one interior scene I had displacement on the floor and there was no problem with IM calc. I added displacement on some chairs, rendered a region and it worked fine. I then added displacement for a small bowl before I rendered the whole image, and during the night vray didn't even calculate the first IM pass. IM was estimated to take 450 hours...

Same goes for the first interior I mentioned. I had displacement on a couple of flippers and on a towel. I tried to render a region of the flippers and IM calculated, but when the image was rendering all buckets froze after a while. Even those that did not render the flippers froze. I tried to render the whole image and then the IM didn't even finish calculating...

In the end I calculated IM without displacement and rendered the image with saved IM and LC..