Displacement question

[Sawyer]

I have a scene that uses a bit of displacement. And it is taking ages to render - w/o displacement it takes 40 min.s but I canceled the displacement rendering because it was saying to would take 9 hours. So thats a while. I did save the lc and irr map and I have found that it seems like rendering regions is alot faster (just rendering the areas with displacement) than rendering the whole image with displacement on.

Now I am using auto mode for memory and watching the rendering window I see "unloading geometry" and "presampeling displacement" notices constantly. Now it seems like I see this even on buckets that do not have displaced geometry and that is why it takes so long. Is there another work around? Should I use static memory? I can't really verify but this is my first project using 1.5 final and the displacement seems to be taking forever.


Thanks

[vlado]

You need to increase the Dynamic memory limit parameter in System rollout and also you can try increasing the Edge length for the displacement (or use 2d displacement instead).

Best regards,
Vlado

[Sawyer]

Thanks Vlado - I am not using dynamic I am using Auto mode should I switch?

edit - what should it be set at?

[vlado]

Displacement always uses dynamic memory regardless of what is set for the Default geometry option (it is just for plain meshes). Depending on how much RAM you have for this scene, you could try 800 MB or more.

Best regards,
Vlado

[Sawyer]

So I upped it to 1500 and it rendered pretty well. My follow up question is how much is the displ affected by gi? The hardest part of this rendering is the lc cal its really small but it takes 15 mins to calc and it will crash if I am not careful. But I can save out the lc and the irr maps w/o the displ in 2 mins and then render with. It looks pretty good and takes a fraction of the time it would if I was calc'ing the displ.

[Sawyer]

So here is a sample. This was pre calc'ed without displacement and then rendered with. I think its pretty good. I know there are aa issues that will be cleaned up but this rendered in 1h17 which is down from the 9+ it was saying before.

[vlado]

For relatively small displacements, this will work fine.

Best regards,
Vlado