V-ray for Unreal - vrscene compatibility - Subsurface and ALSurface

[suraj_agarwal]

Hello,

I am trying to set up a workflow to render characters (scenes with lights and materials - ALSurface and other V-ray Subsurface Shaders) from Maya and Houdini - in Unreal Engine and I would like to retain the lights and materials exactly from the mentioned DCC apps. I understand that vrscene is compatible so can you please help with a tutorial/documentation to help me achieve this? Also, how to make sure that I am getting the exact same render in all applications?

I am not proficient in Unreal Engine as I am in Maya and Houdini which is why I am hoping a .vrscene will help me.

I understand that V-ray is available for Maya and Houdini and I shall be going for the V-ray collection (sweet deal!), but due to certain pipeline restrictions, I am planning to render part of the final product (characters) in V-ray for Unreal Engine. I do not care about real time rendering as well, I actually prefer it being offline rendering in UE.
I hope to render as photorealistic humans as possible. Any help would be highly appreciated.

Thank you
SJ

Apologies if I posted in the wrong section.

[Alexander.Atanasov]

Hi SJ,

I am trying to set up a workflow to render characters (scenes with lights and materials - ALSurface and other V-ray Subsurface Shaders) from Maya and Houdini - in Unreal Engine and I would like to retain the lights and materials exactly from the mentioned DCC apps.

Unfortunately V-Ray for Unreal doesn't currently support ALsurface and Fast SSS2 mtl when importing them in UE and they will look pink in the viewport. There is an option for the unsupported materials that you can use called Render material from .vrscene. It will use the material that is stored in the .vrscene at render time. You may need to do for a lot of materials because support for V-Ray for Maya and V-Ray for Houdini is not that high. There are specifics for .vrscenes exported from those DCCs, which have not been implemented currently. This is mainly because V-Ray for Unreal is initially targeted for ArchVis and development for VFX and characters may come later in time.

I understand that vrscene is compatible so can you please help with a tutorial/documentation to help me achieve this?

In the Docs page here Quick Start Guides are listed all the currently available tutorials for V-Ray for Unreal. Please note that they are all targeted for 3ds Max.

due to certain pipeline restrictions, I am planning to render part of the final product (characters) in V-ray for Unreal Engine. I do not care about real time rendering as well, I actually prefer it being offline rendering in UE.

Can you please elaborate on the reason for leaving the DCC environment and going into Unreal if you are not interested in the real time feedback UE provides?

Best regards,
Alexander

[suraj_agarwal]

Hello Alexander,

Unfortunately V-Ray for Unreal doesn't currently support ALsurface and Fast SSS2 mtl when importing them in UE and they will look pink in the viewport. There is an option for the unsupported materials that you can use called Render material from .vrscene. It will use the material that is stored in the .vrscene at render time. You may need to do for a lot of materials because support for V-Ray for Maya and V-Ray for Houdini is not that high. There are specifics for .vrscenes exported from those DCCs, which have not been implemented currently. This is mainly because V-Ray for Unreal is initially targeted for ArchVis and development for VFX and characters may come later in time.

I had gone through the documentation shared by you but one thing was not working for me in particular, which was External Material Libraries.
The documentation mentioned to edit the vraysettings.json file to use materials outside Unreal with the help of V-ray material instance but I cannot find the file to edit in the location suggested by the document i.e. C:\Program Files\UE_4.26\Engine\Plugins\VRayForUnreal\Content
The V-ray Fast SSS2 mtl and other materials worked for me using the "Render material from .vrscene" option, but the ALSurface shader does not. Is there any other setting that I am missing?

Can you please elaborate on the reason for leaving the DCC environment and going into Unreal if you are not interested in the real time feedback UE provides?

The reason for me to go to V-ray Unreal and the leave the DCC environment is to render Metahuman Characters by Epic Games which can only be rendered in Unreal Engine. They can be taken outside UE and tweaked however necessary but it finally has to render in UE. Hence, I am trying to devise a pipeline in order to use the .vrscene workflow to render just the characters in Unreal and the rest in Houdini. Hoping the lights and material match enough to composite it later. If there is any other better way to achieve this, please let me know!

I am also looking forward to Solaris support for V-ray which I believe is in beta right now.

Thank you,
SJ

[Alexander.Atanasov]

Hi SJ,

The documentation mentioned to edit the vraysettings.json file to use materials outside Unreal with the help of V-ray material instance but I cannot find the file to edit in the location suggested by the document

Yes, sorry about that. We removed the shipping of the .json file with V-Ray for Unreal a while back and forgot to update the docs. I have updated them and you can downloaf that jsonfile from here: vraysettings.json

The V-ray Fast SSS2 mtl and other materials worked for me using the "Render material from .vrscene" option, but the ALSurface shader does not. Is there any other setting that I am missing?

There aren't any additional settings for that option. I did a quick test and it rendered fine. Could you send a sample vrscene so I can test it?

The reason for me to go to V-ray Unreal and the leave the DCC environment is to render Metahuman Characters by Epic Games which can only be rendered in Unreal Engine

I understand but I don't think that we will be able to render the meshes and materials for the metahumans. V-Ray for Unreal doesn't support deformable meshes(skeletal or alembic cache files) only static ones and also doesn't support the hair, skin, and eye shaders at the moment. We may implement those in the future.

I am trying to devise a pipeline in order to use the .vrscene workflow to render just the characters in Unreal and the rest in Houdini. Hoping the lights and material match enough to composite it later. If there is any other better way to achieve this, please let me know!

Cannot think of anything at the moment. Will let you know if I come up with something else.

I am also looking forward to Solaris support for V-ray which I believe is in beta right now.

Yes, there is some work being done but cannot provide any more info on the matter.

Best regards,
Alexander

[suraj_agarwal]

Hello Alexander,

There aren't any additional settings for that option. I did a quick test and it rendered fine. Could you send a sample vrscene so I can test it?

Apologies, my .vrscene export directory was wrong. It showed up after I changed the directory. (opened the .vrscene in text editor and quick search and replace did the trick). Alsurface shader did pick up fine but I am unable to get displacement through. Is there a trick or a workaround to get displacement in Vray for Unreal? If you can share some example files where the .vrscene can retain displacement, that would be great!

I understand but I don't think that we will be able to render the meshes and materials for the metahumans. V-Ray for Unreal doesn't support deformable meshes(skeletal or alembic cache files) only static ones and also doesn't support the hair, skin, and eye shaders at the moment. We may implement those in the future.

That's quite unfortunate. I shall look into the workflow amendment as well.

Thank you,
SJ