USD - not able to overwrite

[Mikhalenko]

Hello,
I work in connection Houdini -3ds max. And I save my scene from Houdini in USD format, and load it to 3ds max via VrayScene. But once it loaded, and I want to overwrite again my USD file. I got an error in Houdini that USD files cannot be overwritten, as Access denied, it's happens because it loaded in 3ds max. Any change to check it? May be it happens because Vray streaming file from disk?
Error in houdini:

   Error   Failed to rename temporary file 'p:\MI_house.v006.hksitq' to 'p:\\MI_house.v006.usd': Access is denied.
   ​

[Mikhalenko]

btw, 3ds max 2022. V-rat 6 update 2 (6,20,00 build 00000)

Also I found a few issues:
-when set mode to Geometry, but not assigning material, it's render ok, but once Material (vray material in my case) assigned to VrayScene, it's lead to crash
- also one that I already addresed to ForestPack team: I have trees done in Houdini and saved in USD format, I load them in 3ds max, via VrayScene. It's render as expected, then I scatter them using ForestPack and rendernot correct. It's render it like viewport preview in vrayscene. if I change viewport preview to full mesh in vray scene, it's start render normal . But after a few changes of mode, it's starts glitching, and it's render previous viewport mode, not currently chosen, after each changing mode, i stop and start again render. Also on render when mode in Full Mesh, and scattered with FP, some issue with Noramls on scattered object, it start looks like don't have smooth groups

[tanya_to]

Hey Mikhalenko, Have you tried loading the usd file via USDStage object in 3ds Max and are you getting the same error in Houdini when updating the usd file there? Does it happen with Arnold as a renderer? Regarding the crash with Geometry mode of VRayScene object I'm able to reproduce it on my side and I'll log it in our bug-tracking system. You can override usd materials with Assign USD materials option in USDStage node. Once you click the button, a Multi/Sub-Object material is created, where you can replace the USDPreview surface material with VRayMtl. Is there any specific reason for using VRayScene object for loading the usd file. I'm looking into issues with Forest Pack usd instancing and I'll write back when I have more information.

[Mikhalenko]

Hey Mikhalenko, Have you tried loading the usd file via USDStage object in 3ds Max and are you getting the same error in Houdini when updating the usd file there? Does it happen with Arnold as a renderer? Regarding the crash with Geometry mode of VRayScene object I'm able to reproduce it on my side and I'll log it in our bug-tracking system. You can override usd materials with Assign USD materials option in USDStage node. Once you click the button, a Multi/Sub-Object material is created, where you can replace the USDPreview surface material with VRayMtl. Is there any specific reason for using VRayScene object for loading the usd file. I'm looking into issues with Forest Pack usd instancing and I'll write back when I have more information.

Hello. I tried to use 3ds max usd before, but it was not very smooth, in this particular case I haven't tried it. Reason why I use VrayScene it's because not all our workstations and render slaves have plugin for USD, and as it still in development we can't install it for all our computers, so VrayScene become like universal solution. Also I'm noticed that loading USD scene with vraysScene not bring camera from houdini. Also I have scene assembled in Houdini Solaris with Vray and tried to open it in 3ds max using VrayScene and result was far from identical, as materials, some effects like fog was not working

[tanya_to]

Thanks for the clarification. Yes, the camera in the usd file can not be loaded via VRscene object. As a workaround you can export the camera separately to usd file and then import it in 3ds Max via File/Import menu - from the dropdown select usd file extension, choose the usd file and it will be imported as 3ds Max Physical camera. Effects like VRayEnvironmentFog are not supposed to work for the time being. You can refer to our documentation page for all supported features and temporary limitations https://docs.chaos.com/display/VMAX/USD. Regrading the materials -could ypu send me the usd file? Also, it would be helpful if you could send the usd file that you are instancing with Forest Pack.

[Mikhalenko]

Thanks for the clarification. Yes, the camera in the usd file can not be loaded via VRscene object. As a workaround you can export the camera separately to usd file and then import it in 3ds Max via File/Import menu - from the dropdown select usd file extension, choose the usd file and it will be imported as 3ds Max Physical camera. Effects like VRayEnvironmentFog are not supposed to work for the time being. You can refer to our documentation page for all supported features and temporary limitations https://docs.chaos.com/display/VMAX/USD. Regrading the materials -could ypu send me the usd file? Also, it would be helpful if you could send the usd file that you are instancing with Forest Pack.

Can you please give me your email, so i will send yoy file for Forest Pack and also other usd that have problem with asigning materials in Geomtry mode in VrayScene

[tanya_to]

tanya.todorova@chaos.com

[Mikhalenko]

tanya.todorova@chaos.com

I just cheked with MaxUSD loader, and it's the same error in Houdini when i try to overwrite file