What is supported from UE4?

[uforis]

It would be great to have some documentation of exactly what is supported in Unreal with the VRay plugin. We need more information about using the VRay materials in Unreal, and how to do tessellation or another way to implement displacement with them, and whether or not basic things like the Landscape editor, are in some way supported, as I've had a tough time trouble shooting a lot of this stuff. Really I must say that this plugin crashes WAY too often for me to want to spend any money on it, like literally any step along the way with creating a VRayMtl, has crashed the software. ANY check box potentially crashes the editor. It just seems like the integration is not quite 100% yet, although when I do get it to work I am very encouraged that it is the path forward for our company. I'm still on the 30 day trial, but as it stands right now this plugin is incredibly unstable and is in my opinion really far away from being production ready, especially when the documentation is very sparsely populated with information about what UE4 tools are supported, and how to make them usable if they are supported, etc.

[s.balabanov]

Hi uforis,

Thanks for sharing your feedback. I realize experiencing crashes can be frustrating, so thank you for reaching out.

We do have documentation regarding the supported features on import and rendering. It can be found here:
https://docs.chaosgroup.com/x/T04jAg

Is this what you are looking for? If not, what is missing? How can we improve it?

We do not support tessellation/displacement and Landscape objects yet. Both are on the to do list, though.

As for the crashes you are experiencing, would you mind sharing more information about the circumstances. Have you tried contacting our technical support? We do test the plugin for stability, but we cannot check every possible scenario. The behavior you describe is unexpected and might be due to various reasons, so please do get in touch with us to try and resolve the issues. Any logs, crash folders, dump files and steps or assets to reproduce a crash will help us. You can reach the support team at support@chaosgroup.com or post here on the forums if you feel more comfortable.

I look forward to getting more info.

Best regards,
Simeon

[uforis]

Hi S. Balabanov,

Thanks for your response. I guess in my searching I just missed it. The documentation helps a lot. I guess anything in the engine that is not in that document won't work at all? That's a real bummer because it would be so great to be able blend materials in some way, inside of UE4 that is. I've resorted to authoring my assets with the material blends outside of UE4 in Substance or Quixel mixed for now, but if you can recommend another approach for doing some kind of vertex painting/material blending that would be awesome.

I'm looking forward to seeing the displacement features.

Almost all of my crashes have to do with changing between UE4 materials, VRayMtl, and the VRayPBRMtl. for instance, sometimes the drop downs for changing the Blend Mode and Shading Model, to either Opaque, Masked, or Transparent in accordance with the docs, the drop down will appear black and then crash. It seems the compiling of the shaders often fail, and then crash. Changing the texture samples has also crashed a number of times, and I've just been testing with jpegs, nothing crazy. The crashes occur often in the material instance editor, but can also occur in the graph editor.

This could have something to do with the out of the box UE4 settings. Are there any changes or performance optimizations for the engine that you can recommend that may help the issue? I'll see about creating a package of my project for your evaluation, but the problems I'm having with the crashing may have more to do with my local machine.

[uforis]

One other little tid-bit of feedback is that the "Show VRay Message Window," in the VFB, doesn't seem to do anything. Is there any way to see the progress of the render as progressively refines the noise?

[Alexander.Atanasov]

Hi, uforis

it would be so great to be able blend materials in some way, inside of UE4

You can use Materials with attributes in material functions and blend them in the "Master" material. The new material layering, however, is not yet supported but it will be in future builds. The old blending way is supported as long as the expressions used in the material functions are supported.

Almost all of my crashes have to do with changing between UE4 materials, VRayMtl, and the VRayPBRMtl. for instance, sometimes the drop downs for changing the Blend Mode and Shading Model, to either Opaque, Masked, or Transparent in accordance with the docs, the drop down will appear black and then crash. It seems the compiling of the shaders often fail, and then crash. Changing the texture samples has also crashed a number of times, and I've just been testing with jpegs, nothing crazy. The crashes occur often in the material instance editor, but can also occur in the graph editor.

Sorry to hear you are having all those issues. They sound like Unreal related issues and not V-Ray ones. Do you experience such issues with the plugin disabled? What hardware are you running? You can try to change your editor scalability quality settings from Settings > Engine Scalability Settings and pick from the presets Low, Medium, High, Epic, Cinematic and see if there is any change to performance.

the "Show VRay Message Window," in the VFB, doesn't seem to do anything. Is there any way to see the progress of the render as progressively refines the noise?

Yes, the "Show VRay Message Window" button is non-functional at the moment but we are working on fixing this. We are also working on a progress bar. Meanwhile you could see the Unreal output log which you can open from Window > Developer Tools > Output Log. There all actions are printed and you can filter them to show only V-Ray related ones.

Best regards,
Alexander

[uforis]

Hi Alexander,

thanks for you feedback. Interesting, i'll try this method for blending materials.

As for the crashing, I am running several other projects without the VRay plugin enabled and experiencing no crashing, so it's hard for me to imagine not having anything to do with the plugin right now. But I'll keep testing. Like it said, most of the crashes happening when changing the blending modes in the VRayMtl from the Alpha Blended state to Opaque or Masked.

[uforis]

I'm sorry if this is a silly question, So could you then copy and paste all of the VRayMtl nodes into a material function and put in your texture samples there directly, connect them to the make attributes node and output that, and then in a new UE4 Material, instance that new VRayMtlFunction and blend between 2 VRayMtls? seems fairly complicated but I guess it might work?

I'd also like to point out that the documentation does not show that the MatLayerBlend_Simple node is supported. Are there any other useful nodes not in the docs that are useful here?

[Alexander.Atanasov]

Hi, uforis

most of the crashes happening when changing the blending modes in the VRayMtl from the Alpha Blended state to Opaque or Masked

This is very strange since the VRayMtls are native Unreal materials with no modification from our side. We only have those 3 materials mapped with V-Ray ones. Can you please send us a simple sample project where this is occurring to try and replicate it?

could you then copy and paste all of the VRayMtl nodes into a material function and put in your texture samples there directly, connect them to the make attributes node and output that, and then in a new UE4 Material, instance that new VRayMtlFunction and blend between 2 VRayMtls?

I am afraid that this is not going to work that well. If you do that we will treat the material as Unreal one and not all expressions and nodes in VRayMtl are supported at the moment and the rendered result may not be as expected. We are working on a way to use VRayMtls for layers but i cannot give ETA on that functionality. Can you explain your workflow how are you using them now and how are you imagining to use layered materials in the future?

the documentation does not show that the MatLayerBlend_Simple node is supported. Are there any other useful nodes not in the docs that are useful here?

The MatLayerBlend_Simple node is not mentioned because it isn't a single expression itself. It is a material function which if you open, you will that it has expressions such as Lerp, BreakAttributes and MakeAttributes which are supported. In the docs are listed the basic building expressions which are used in all material functions such as MatLayerBlend_Simple, CustomRotator, Fresnel_function, etc. If the expressions used in those functions are supported then you will be able to render/bake them.

Best regards,
Alexander