V-ray proxy with custom preview: how to do it and keep the proxy multisub material?

[Antioche]

Hi,
I've been struggling for a day trying to create SketchUp Vray proxies with a custom proxy preview, but I have not yet managed to get a good workflow.
I am trying to create a SketchUp file that contains a Vray proxy object (say a chair), but with a low-poly version of that chair (generated with the Skimp plugin), so that the chair would look good in SketchUp (rather than the weird looking low poly mesh without material automatically generated by Vray on proxy creation...), yet render perfectly in Vray.

Here's what I am doing:
- open high poly model in SketchUp
- Duplicate it and make it low-poly with Skimp plugin
- Duplicate original high poly object and export it as proxy vrmesh with the Vray plugin. It is replaced in SketchUp by the Vray proxy with the mesh preview automatically generated by Vray

If I then export (Component > Save As... in SketchUp) that proxy component, it renders normally when reimported in another SketchUp file and rendered with Vray. But it looks bad in main SketchUp display, which I would also like to export as line drawing...

I would like to use the Vray proxy "Custom preview" display option to show the low-poly version of the chair in SketchUp, while keeping the full poly render in Vray.
But if I paste the low-poly version inside the proxy component and re-export it, it will not render the materials in teh proxy when reimported in another model...

What is the correct way of defining a custom preview for a proxy? What is the hierarchy of the group/components inside the proxy?

Solving this would be a fantastic improvement of my rendering workflow.
Looking forward to your help.

Best regards,

Thibaut

[jiminy-billy-bob]

Transmutr can do that with just a few clicks: https://transmutr.com/
It can either generate a simplified model directly (like Skimp), or you can feed a SketchUp file that will be used as the proxy custom preview.
It handles everything for you, you don't have to worry about hierarchy and materials.

More info: https://help.transmutr.com/manual/geometry-tab/proxies

[Peter.Chaushev]

(...) I would like to use the Vray proxy "Custom preview" display option to show the low-poly version of the chair in SketchUp, while keeping the full poly render in Vray.
But if I paste the low-poly version inside the proxy component and re-export it, it will not render the materials in the proxy when reimported in another model...

Once you have the high-poly proxy set up with its original preview, change its Preview Type parameter to Custom. Then unlock the group within its skp component and replace the original preview faces with the low-poly object you've prepared. Make sure the proxy MultiMaterial is applied on the new preview object. Finally, lock the updated group within the component and you're all set.
There is V-Ray core functionality which allows choosing custom .vrmesh preview upon proxy creation. We plan on exposing it in the next upcoming update or the one after.

Kind regards,
Peter

[Antioche]

Hi,
Thanks for the tips!

jiminy-billy-bob: I had looked into Transmutr and that looked very good, but ended up trying Skimp instead for two reasons: there is no mac version of Transmutr yet (I'm working on a mac system) and it is not able to simplify SKP files, so that I cannot use it for 3D Warehouse assets.
They are working on both of these issues, so I'll probably end up using Transmutr in the future.
Regarding simplifying SKP files from the 3D warehouse, I know that it is possible to export 3D warehouse assets directly as Collada (.dae) files, which Transmutr can process. Have you tried to use that workflow?

Peter.Chaushev:I have managed to structure the proxy as you described and it works as expected. Only limitation is that on swapping the proxy preview in the proxy settings (to bounding box, for instance) seems to delete the custom preview and it is not possible to display it back afterwards. Or am I missing something?

Cheers,

Thibaut

[Peter.Chaushev]

Only limitation is that on swapping the proxy preview in the proxy settings (to bounding box, for instance) seems to delete the custom preview and it is not possible to display it back afterwards. Or am I missing something?

This is expected behavior. The custom preview is currently not stored when switching between modes.
There are a couple of improvements the team have in mind which may directly affect this problem.

Kind regards,
Peter