Roughness does not seem to affect reflections in mobile (Android)

Development Rendering
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1

Hi,

Roughness does not seem to have any impact on reflections on a material on mobile builds. I made a small test level containing a simple environment and three spheres. I used a SphereReflectionCapture actor to get the reflection data. The spheres use a very simple material that uses the default lit shading model and consists of a base color and a parameter for roughness. From left to right the roughness of the material on the spheres are 0 → 0.5 → 1. The app was launched in development mode.

Here’s what they look like in the mobile preview:

44860-3+spheres,+mobile+preview.jpg
44860-3+spheres,+mobile+preview.jpg1283×723 183 KB

The reflected environment fades away as roughness increases.

Here’s the same shot from a Samsung Galaxy S2 (GT-I9100, Android version 4.1.2):

44862-3+spheres,+samsung+galaxy+s2.png
44862-3+spheres,+samsung+galaxy+s2.png800×480 296 KB

The reflected environment can still be seen in the sphere with the lowest roughness. It just doesn’t seem to fade as it does in the mobile preview.

Is this a limitation on mobile platforms or a bug? Limitation on the S2 in particular? Is there any solution?

Thanks

2

Hi PerWikman,

There are indeed limitations on mobile platforms. Please see this documentation for development for mobile using UE4, and double check against your materials.

Thanks!

3

Yes, I’ve read those articles. The bFullyRough flag does remove the reflection, but makes the material fully rough. Is that my only option? Some of my materials with high roughness tend to look bad, am I better off just making them fully rough? The reflection tends to make them appear very glossy.

4

Hi PerWikman,

Here is a useful forums thread about how to correct reflection spheres for mobile. Does this help your results?

5

The problem is that the S2 almost guaranteed doesn’t support the GL extension needed for variable roughness. Can you try on a newer device?

6

That’s actually exactly the way my scene is setup. It did not help with the reflections though. But as Josh said, there might be a limitation in the actual device.

7

No, that’s the only device I have access to at the moment.