Vray 3 Maya Proxy Subdivision Problem

[brickyard]

Hello,
I'm using Vray 3.05.04 (api version 201400) in Maya 2014 Linux. Working with some high resolution (2mil+ faces) multi-object models, where most meshes are attached to a shared subdivision set, but some are not meant to be smoothed, when generating a proxy and rendering that proxy, subdivision is not preserved. Alternately, I have tried attaching the subdivision attributes to all the desired meshes, and that is also not being preserved through the proxy process. If I retopologize every single mesh to be subdividable (not ideal for this project) and then take the resulting proxy and add a subdivision set to that in the render scene, it will subdivide everything, but on such large scenes this crashes the render (I believe because this is reloading the geometry and not getting the benefit of the proxy, but I could be wrong), and it's not really a valid solution anyway as I need the fine control on which meshes should and should not be subdivided at render time. At the moment, I'm being forced to smooth my meshes in maya before creating proxies at 1 level (creating significantly giant sized files) and not subdividing anything during rendering. Can you please let me know if there's some valid workaround for this, or if this is a bug which can be fixed in a nightly build and soon. Thanks so much!

-David

[asen.atanasov]

Hi David,

I will try to help you out. One option is to use the export option "Export each selected option in a separate file". Then you can add subdivision as usual (attrubutes->VRay->Subdivision..) to the nodes, that you want. In this case the subdivision will be performed at render time. Another option is to use alembic files and the new subdivision options at the bottom of proxy's "Alembic proxy parameters" rollout. Before alembic export from maya, you should add "SubDivisionMesh" attribute to the Shape and set it to "true". In this way alembic will write SubD object, which we will recognize and subdivide at render time. You have subdivision level control in the rollout. If you want to cache many meshes into single file, and subdivide just some of them at render time, the latter suggestion is your only option.

Is this working for you?

Best regards,
Asen

[brickyard]

Hello Asen,
Thank you for the reply and help. So, I've tried both things, and this is where I am (they aren't working for me at the moment). In the first case, I tried doing the "export each selected item in a separate file" in a small test scene with a cube, sphere, and cone. It indeed does work at you stated. However, when I try to do this export for my real stuff (cars with around 600-700 parts at greater than 2mil faces), the export ends up crapping out part way through, and then my machine won't fork any other processes so I have to reboot (16-core Z820/24gb mem/Linux). I then tried the alembic method. When I write one of the cars out and load it to test render, unlike the vrmesh, it is not rendering the shaders, just the default maya shader. In the VrayMesh node, under the Shaders rollout, I have tried this in all three settings (global/maya/proxy) all to no avail. I have tried exporting the Alembic cache as both versions from Maya (HDF5 and Odawa), both as Export Selected and as Export All, with the same result. Am I doing something wrong in regards to loading the Alembic file into the VrayMesh node, causing it to not load shaders? Any help on this would be appreciated. Thanks again!

-David

[asen.atanasov]

Hi David,

First concerning the alembic method, unfortunately the materials won't be reassigned and you have to do it manually. Maybe me have to look for a way to do it automatically, but currently we don't have this option.

Probably the problem with the vrmesh approach is that you have to write hundreds of files, and something goes wrong. I suggest to use the vrmesh export with "Export all selected meshes in a single file", and group the different meshes into groups. One group for all the meshes without subdivision, other groups for the meshes with identical subdivision parameters. It this way you will reduce the number of vrmesh files, and still have the node subdivision control for the corresponding sets.

I suggest this workaround. Please, let me know it is working for you. You can also send a scene, or part of a scene by contacting our support at support@chaosgroup.com, and we can look for a better solution.

Best regards,
Asen

[brickyard]

Hi Asen,
Well, while using two separate exports per item could be a forced workaround, that really won't work with what we're doing as the whole idea is to have a single proxy for each car in our scene that can be subbed out with different proxies as needed for the requirements of the production. Since VRay is encoding the shared object properties nodes for things like object ID sets and other things, the most ideal solution would be for VRay to additionally encode the subdivision information in a shared subdivision node and pass that through properly. Can that be added to the fix list as this is really the ideal solution?

-David

[asen.atanasov]

Hi David,

I understand and we will discuss what would be the best solution.

Best regards,
Asen

[brickyard]

Thanks so much, I appreciate it. I know this will come up again and I definitely want to be able to take advatange of the proxy system on scenes with hundreds of large models (cars and such) in giant crowds, and be able to maintain my pre-setup subdivision and displacement sets.

-David