what settings for a 'perfect' reflector?

[shadowphile]

I'm trying to create a virtual lightprobe of my scene, so I'm rendering a view with an ortho camera of a mirrored ball.
The reflection values don't make sense to me though, especially the reflection value.
I either get too bright a ring on the edges of my ball, or too dark a sky.
Are there settings that will just give me perfect reflections?
thanks

[Matt]

Theoretically, if you set Index of Refraction high enough, you should get a perfect reflector. Unfortunately there are approximations in the IOR calculations which make it give incorrect results. At high IOR the glancing angles start to become darker. I will look into this. You also need to set specular roughness to 0 because it subtlely influences the maximum reflection angle.

I'm afraid I can't think of any way to get a perfect uniform reflector with any of the current shaders. The idea is that high IOR would give you that, but it doesn't

Rendering from multiple angles and blending the unwrapped images in post is the only solution I can think of, but you may as well render cube faces if you do that.

Matt

[shadowphile]

thanks Matt.  That's good to know about reflectors anyway, but I'm now leaning away from the lightprobe approach.  It may be only one render but the technique requires massive resolution and detail in the final image and 6 cube faces distribute those demands around.