Unreal Engine No Roughness on Opacity Map

Bulldog3dz

I've created this glass material in Substance Painter and have exported the textures using the "Unreal Engine 4 (Packed)" setting. 

Everything looks good Substance Painter and the UE4 Material view. The material has opacity and roughness values.

However, when you view the material in engine. The opacity is working correctly, but the Roughness values aren't showing at all. It doesn't see the Roughness values at all. 

I've attached some screenshots of my Substance Painter/UE4 Material Set Up/UE4 Viewport. 

Few questions/thoughts...

1. Why is the Roughness not appearing correctly in UE4?
2. Can Roughness and Opacity not be used at the same time on a material?
3. Could this be an issue with something like the reflection probes/lighting?

Any help would be greatly appreciated.

Thank you

macoll

Add more parameters to your material to enhance the roughness rendering ^^

By example, a good tutorial would be --> https://www.youtube.com/watch?v=5R30e7q_Xdw 

Keep up!

poopipe

that tutorial tells you to use a separate cubemap for reflection so it's an instant fail for me - This is the right place to start: 
https://docs.unrealengine.com/4.27/en-US/RenderingAndGraphics/Materials/HowTo/Refraction/


Roughness and opacity can be used at the same time - you might need to artificially increase opacity where you want the glass to appear rougher though as it is quite hard to see fully transparent things


Painter's viewport uses a similar shading model to Unreal but you can't directly compare results on any material since the lighting is significantly different 
and 
I'm not sure translucent materials will show in the roughness viewmode - it would be reasonable if they don't since it's a different render path from opaque materials