What is "Building embree static accelerator"?

[djanim8]

I have a VRay/Phoenix render that gets stuck on "Building embree static accelerator" and crashes, and I'm not sure what it's doing. Could someone explain what VRay is doing at that point so I can try to adjust what I need to keep it from crashing?

[yavor.rubenov]

Hello,

That is the moment V-Ray builds its acceleration structures that help for faster ray-scene intersection.
Generally it requires quite a lot of system memory so a crash there might mean that you are running out of memory. If that is not the case then maybe it is something scene depended - could you share the scene with our support ?
One other option - when Max crashes it should create a crash dump - it is located in the temp folder and is called 3dsmax_minidump.dmp - if you could attach one such dump it also might help.

Best regards,
Yavor

[djanim8]

I uploaded a file to the FTP server named "RainTestChaos.zipx" The machine I was attempting to render it on only has 16 gigs of ram, and a 8 core 2.9 HGZ Xeon processor.

If you could give me some info on how to edit the scene so it doesn't require as much RAM, that would help. The scene is pretty simple. It was only a test to see if I could do rain drops in a phoenix grid.

[georgi.zhekov]

Looks like you run out of memory - even without Phoenix the scene takes about 20 GB of RAM.

You are using some pretty large texture files paired with FullHD resolution - you can either use lower resolution textures or lower the final image resolution.

[djanim8]

Thanks, I'll give that a try and see if it works!

[djanim8]

Dropped the HDRI image to 8k width, and the one texture in there to 2k. I set the rendering resolution to half of full HD. It still froze the computer and crashed. This scene isn't nearly as large as some of the other ones I've done on this machine, is there anything else that might be causing it?

This machine is harder to update with the nightly builds... so it's running on the original Phoenix and VRay. Would it help if I attempt to get that updated?

[stevirtvr]

djanim, Do you have a large area that has a material with a displacement map? I have a file I have been using for several days and have had no issues. Then today on about the 5th rendering my computer froze up as my ram was maxed out. It didn't matter whether I had embree turned on or not. After an hour of trial and error I finally figured out that this particular camera had a large area of driveway pavers that had a material with a displacement map. I turned off the displacement and it rendered no problem, with ram usage at 50%. Maybe an issue with the latest VRAY build?

[djanim8]

Yup, removed the displacement map and it rendered fine!

[yavor.rubenov]

The change related to displacement in recent V-Ray builds is that by default 3D displacement is now using static geometry - it requires more RAM but renders faster. You could change that in the VRayDisplacementMod settings - there is a checkbox "Static geometry". When it is off the displacement will be rendered as dynamic geometry and will obey the dynamic geometry limits.

Best regards,
Yavor

[djanim8]

I was just using it on the material itself, not the modifier.. does that make a difference too?

[yavor.rubenov]

Yes the displacement in the material is also generated as static geometry. You can control it's edge length in the Render Setup -> Settings -> Default displacement