.vrscene Shader Reflection

[bernhard]

Following issue:
--> export a .vrscene
--> import into Unreal

VrayShaders that don't have any reflection, appear high reflective inside the Unreal Engine.
Even if the Reflection Color is black - meaning, there is no reflection at all.

Can you reproduce that issue on your end?

Watch Video here:
https://youtu.be/f7tzLBXc4dQ

[Alexander.Atanasov]

Hi, Bernhard

This reflection that you see i the sphere is the specular refection of the Rect Light which you can control manually by tweaking the Specular Scale. The V-Ray shader in Unreal is based on the Unreal native material but created in a way to simulate the V-Ray physical shader. For some reason Unreal doesn't respect the material's Specular value, which control the reflection properties of the material. Similar to the Reflection parameter in V-Ray 0(Black) means no reflection and 1(White) means full reflection. When we have Reflection set to Black that sets Specular value to 0 which should disable all reflections. However that doesn't seem to stop the specular reflection of the Rect light. I think this should be an issue that Unreal has to fix but we will investigate if we can do anything about it.

P.S. If you change the Reflection gloss value from 1 to 0, the reflection will reduce.

Best regards,
Alexander

[bernhard]

Hmm.. it would be cool if we can make sure that all the VraySahders we import with the VrayScene will recognize that and automatically set the specular output to the right values.
For example.. if there is no spec inside the original VrayMaterial, then let's make sure a node will be created that sets the unreal material also to 0.
And same for reflection...

That should be doable, right?

[Alexander.Atanasov]

Hi, Bernhard

Hmm.. it would be cool if we can make sure that all the VraySahders we import with the VrayScene will recognize that and automatically set the specular output to the right values.
For example.. if there is no spec inside the original VrayMaterial, then let's make sure a node will be created that sets the unreal material also to 0.
And same for reflection...

This is already done for the V-Ray shader material. In the example below there are 2 lights, the left is a sphere light and the right is a rect light. When you tweak the Specular (in the first example link with Unreal material) value and the Reflection (in the second example link with V-Ray Mtl) value you can see that the specular reflection of the sphere light is fading but not for the rect light.

https://ftp.chaosgroup.com/support/s..._UnrealMtl.gif

https://ftp.chaosgroup.com/support/s...ug_VRayMtl.gif

The reflection that you are seeing in the shader ball from the rect light is a bug from Unreal. You can remove that reflection if you lower the Specular scale of the Rect light to 0.

https://ftp.chaosgroup.com/support/s...cularScale.gif

Best regards,
Alexander