In my setup I have two environment textures applied to my world. They are mixed using the factor of
Is Camera Ray, like so:
The first environment node has a color grid, which is used for illumination. The second has a uv grid, which is shown to the camera.
So far, so good. If the scene is rendered with diffuse shaders this works perfectly. But when throwing transparency and reflections in the mix, things go south. Transparent objects will show the illuminating environment (color grid) rather than the one that is visible in the render (uv grid). Here's a quick render to illustrate the problem:
I can see why this is happening so probably I will need to look for an alternative route. Suggestions are very welcome!