Worksession V-ray Materials

Anyone has got a right workflow when dealing with rendering a work session in Vray? Basically i have several files connected together and saved vray materials in each seperately. However materials sometimes render differently depending which work session file is set active. This gives me naturally great headache as i work with a huge model and cannot have only one file.
i work in rhino 5.10 and vray 2.00.25251

Hi Daniel,
I haven’t worked with worksessions yet.
On big projects, I use referenced blocks. And when these blocks are themselves big files, I use a VRMESH in these referenced blocks.
When you open the main file and it reads all the referenced block, V-Ray asks what to do with each material that is already in the file.
Works pretty well.

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Hey Marc,
thanks a lot for advice, this will definitely make my plan B. I will try to ask around in chaos group forum too, out of pure curiosity plus I think there is nice advantage of work session of several people working on parts of the model at the same time.


Hello Daniel,

I’ve worked a lot with worksessions nevertheless i’ve recently encountered some peculiar behaviour in terms of material name management. for example, materials in one referenced file will get automatically “imported” within your main file - which at some point may result in odd behaviour due to the fact that materials get overwritten - if you choose so.

If you have the option, and in case you don t already do so, i would suggest working on a material based layer structure.

According to the McNeel examples they suggest using block references. - either way you will still encounter the material problem if you have shared material names between different files (or if you get materials - through copy+paste actions from one file to another).

I know this problem from vray1.5, that was however manageable by not giving materials in different scene files same name. In vray 2.0 for rhino a new bizzare thing appeared that was also acknowledged as a bug by chaosgroup. To describe it best watch this video.

Chaosgroups has told me they will work on it but couldn’t tell me when it should be fixed. Until know I will try to work with blocks instead, even though worksession is a mighty tool which should be thought about by chaosgroup ASAP.

Strange thing -> good to know. Nevertheless i think that happens because the worksession overwrites the materials. you have 2 files with 2 different materials set. Whichever gets opened first, overwrites the values of the materials in the other file. I think it’s actually what i was talking about in my comment. The workaround is not having same names in 2 linked worksession files…or?

It is a strange thing, but like i said chaosgroup has admitted it to be a bug, i dont think there is a way to work around it. other than avoiding using vray and file session.

Perhaps it is clearer in this vid:

  1. While being in box.3dm i created and applied red box material to the object
  2. I switch from box.3dm to roof.3dm and create there green roof material which i apply to the object
  3. I switch back to box.3dm and change the colour of box material to blue (so far so good)
  4. i switch back to roof.3dm and render it out to find out that the box is green and not blue

so you cannot create materials in different linked files because when switching between files they do not update

and so you would think that solution would be to apply all materials and render only one linked file to avoid this communication problems. This is what happens it you try to do everything in one active file.

so basically you cannot apply material to inactive files.

this is the reply from chaosgroup:
Hello Daniel Mikolajcak,

A member of our support team has replied to your support request:

Yes it is a general bug which has been reported into our bug-tracking system thanks to your feedback.
We are not able to provide any time frames for the solution about the issue, but we will notify you as soon as we have it.

Don’t hesitate to contact us if you have any questions about our software.

We hope this has answered your questions. If not, please just reply to this email.

Yes it’s exactly what i was saying as well. If you create a material in a file and attach the file to another file, it automatically gets copied in the other file.

Once you start switching around, the material gets overwritten whithout you being asked which of the different instances to use.

There is nevertheless a glitch since it sometimes showes up in the viewport differently then in the rendering. It s good to know they are looking into it and i hope it gets fixed soon.