I've been trying to make these work for hours.

The sunlight should be reflecting off the wall and lighting the floor. I've tried the default settings (caustics on) and followed the caustics tutorial in the manual exactly, but it just isn't working for mirrors consistently. As another example, I managed to make them work and reflect it off the floor onto the wall of an interior, then I copied the entire building and moved it over. The caustics in the new building didn't work at all despite using the same materials.

As you can see in the picture, it looks like the caustics are partially there, hence the arrow shape of the light.

Photon radius didn't help in either of these cases. Spotlights/omnilights didn't work either. Faces are oriented correctly.

Sketchup version: 8.0.11752
Vray: 1.49.01