I exported few basic fire VDB sequences and when i try to load them into the Renderman Visualizer, Maya crashes. Here is the first portion of the crash log
//================================================== === Maya Crash Report //================================================== === Exception code: C0000005: ACCESS_VIOLATION - illegal read at address 0xFFFFFFFF Fault address: B81A6A09 in C:\Program Files\Pixar\RenderManForMaya-27.1\lib\2025\OpenVDB.mll 0001:00405A09 Logical offset (see .map file for location)
Happens in Maya 2025 and 2026.
Im using Rendering for Maya 27.2 .
Has anyone else encountered this or have any suggestions?
Embergen VDB’s load okay. The official OpenVDB downloads load okay. Its just PhoenixFD VDB’s that crash it. is there perhaps an additional setting needed for compatibility?
And the PhoenixFD VDB load fine in Arnold Volumes.
I just tried this with Renderman 26.3 in Maya 2025 with a fresh Smoke VDB, and it seems to work (and render) as expected. It’s most likely something Renderman-related, since you say it works in Arnold Volumes.
I was testing it with the Fire sim preset and the Fireplace sample scene to replicate the crash. I still get the crash with the Large Scale Smoke sim preset. Oddly, The Chaos cloud asset VDB works fine. Whats even more strange is if i run the same Fire sim preset in Max 2026 and output as a VDB, those VDB’s load just fine in Renderman for Maya 27.
I wish i could test it on 26 but im using the non-commercial version of Renderman for Maya and they down allow using older versions. Does anyone there have 27 installed?
Confirmed. It instantly crashes when I try to load a Phoenix .vdb in 27.2. It doesn’t crash with an EmberGen .vdb; however, I do not see anything loaded. Is this the case on your end? Either way, I suggest contacting Pixar about this.
Yes, that’s how it is on my end as well. One other thing i noticed is if create a Phoenix sim in 3DS Max and export it as a VDB and load it into Maya Renderman 27.2, it does not crash. Would you have any thoughts as to why Phoenix VDB’s from Max doesnt crash Maya but Phoenix Maya VDB’s do? Does Phoenix write VDB’s differently between Max and Maya?
Vdbs from 3ds Max indeed do not crash Maya, and I figured out how to load and preview them correctly in Renderman - simply switch the Viewport 2.0 engine to OpenGL - Core Profile. I’ve no idea why those from Maya crash it, I’ll ask the devs if there’s a difference in the way .vdbs are written.
it still crashes on me in OpenGL strict and compatibility mode using the Chaos Fireplace sample scene. I hope the devs have some insight regarding the issue.
Okay, the devs took a look and determined that the only difference is the fact that Maya is Y-up, while 3ds Max is Z-up. Some transformations are applied to the .vdb files exported from Maya to consider this, which are probably the cause of the crash in Renderman. If you switch Maya to be Z-up (from Preferences > Settings > World Coordinate System), and export the Phoenix .vdbs like that, there won’t be any crashes. Still, this is a Renderman issue, since it has worked in their previous versions.
Otherwise, what I meant by switching the Viewport to OpenGL is so that the VDBVizualizer actually loads and previews .vdb data.
Hi @hermit.crab , so I spoke to 2 devs at Pixar and what they have determined is the crash is not due to the Renderman code. Its due to the updated OpenVDB library. Its stricter and Phoenix is not compliant with the latest OpenVDB library. Can Chaos devs look into making Phoenix VDB export compatible with the latest OpenVDB library?
Here is the conclusion with my discussion with them:
one of our other engineers took at look at this file on a Windows machine. It seems the crash is being issued in the OpenVDB library, not in our code; Windows immediately issues a segmentation fault simply when trying to open the file. So as far as OpenVDB is concerned, this file is really bad.
As mentioned: there is a density grid that is ill-formed. Whilst the OpenVDB library could probably stand to be more graceful about this, particular on Windows, the fact remains that these VDB files have a density grid that serves no purpose as far as we can tell; perhaps Chaos can be persuaded to change their exported VDB so that this empty grid is not present in the file.
Hi @hermit.crab , So Embergen does have the same issue. You probably downloaded the sample VDB’s from their website. Those actually work fine for some reason. But VDB’s created in the recent version all crash. Similar to Phoenix. I spoke with the developer of Embergen and confirmed the issue and looked into. Here is his report as to whats causing the crash as it may help Chaos devs find a work around.
