Struggling with crashes when using displacement

[Mats_O]

Hi all,

I have been struggling back and forth with crashes when using displacmentmaps. The crashes always happens during the first seconds of the Light Cache calculation. I have always believed it has got to do with too little memory, but now when I render on a new Win 7 64-bit system with 24 GB RAM it still crashes from time to time.

- From a technical/memory management point of view, is there any difference between using a displacement map in a VRay material and using a VRayDisplacmentModifier instead? Which is to prefer?
- When starting a render through Backburner, I do it on a 32-bit system but render on 64-bit system. The problem is I can´t use more than 3000MB Dynamic memory limit (Raycaster), probably due to the fact that I type it on my 32-bit machine. I want more since I render on the 64-bit machine with 24GB Ram.

Any hints?

[vlado]

Is your 3ds Max version itself 32- or 64-bit on the render slaves?

Best regards,
Vlado

[Mats_O]

On 64-bit renderslaves, 64-bit Max is installed.
On 32-bit workstation (from which I send the job), 32-bit max is installed.

[vlado]

Ok then; which V-Ray version are you using?

There is no difference between displacement done through a material and VRayDisplacementMod.

Best regards,
Vlado

[Mats_O]

I am using 1.5 sp4a for x64 on on 64bit renderslaves, and 1.5 sp4 on for x32 on 32bit workstation.

The crashing problem have been sticking around on different 3D scenes during several versions of both 3DS Max and VRay. One thing that is really strange is that if I first override all materials with a simple VRay mtrl, do a render, and then go back to original VRay mtrls with displacement and render again, it does not crash. It is like it needs to reload the displacement map into memory or something...

[Da_elf]

why not update the x32 machine?

[Mats_O]

Since the problem has been around for different scenes, rendering on different machines using different OS and different versions of both Max and VRay I am suspecting a bug. The only common factor is that it happens when rendering scenes using displacments on lofted geometry. Vlado, is this a known problem, something you are working on? Thanks in advance!

[Mats_O]

Is there really nobody who have experienced similar problems and found a workaround or reason for VRay crashing during Light Cache calculation using displacements?

I am in the middle of production and to find a soultion would be highly appreciated.

Thanks!

[SPS]

Thought I might bump this since I started noticing the same behavior. 1.50.sp5 64bit on with no DR. One thing that makes it hard to troubleshoot is that if after Max quick closes (ungraceful shutdown) the next session will render okay if I uncheck the displacement map of a displaced material, then cancel the render, reactivate the displacement bitmap... for awhile. Subsequent renders will eventually kill Max again. I've been watching RAM and the scene never comes close to maxing out.

I also noticed that this only seems to be an issue with the VrayPhysical Camera. A perspective view from the same location renders fine. Did Mats_O ever resolve this?

[vlado]

If you continue to have issues, would it be possible to get us the problem scene to vlado@chaosgroup.com so that we can fix it?

Best regards,
Vlado

[SPS]

Thanks for the request Vlado. Will do. For now, I've been able to work with a fresh scene comprised of merged data from the errant file. No issues yet. I'll e-mail a file if the issue returns. I routinely start new projects by using a previous project's file and deleting objects not applicable. This habit surely has the potential for corruption.

I'll be sure to post here if I run into it again.