[REQUEST] Scene Reflection Capture 2D

anonymous_user_6f08600d
Sat, 27 Sep 2014 09:41:40 +0000
Rendering

So, I’ve been trying to make transparent reflective materials, namely water, and it seems that Unreal’s capability to deal with planar reflections is somewhat limited. As it stands, I’m using quite a limited and very approximate system, placing a Scene Capture 2D on the reflective surface, following the camera. This works okay for objects close to the camera, but fails for objects further away.

What is really needed for accurate, screen space reflections is a second camera mirrored in the tangent of the reflected surface, as illustrated here:

The reflection camera would be roughly similar to a one-bounce raytraced reflection. As it stands, though, this is not possible to achieve, because the reflection camera needs to clip beyond the reflection plane. And object behind the surface, including the surface itself, cannot be rendered, or the reflections will not work. I understand that a misaligned clipping plane is less performant than a simple depth test, but it should still be feasible.

I understand this functionality was built into UDK, but removed in Unreal 4. This is quite surprising, as without it, it is extremely difficult to produce real-time reflections for surfaces such as water or glass, that need to be translucent. It would be a huge improvement to the engine’s functionality to reinstate this feature, as it would finally allow for accurate screen space reflections of planar surfaces, even for objects very close to the surface.

2 posts - 2 participants