Reflect light but invisible to camera

[haffy]

Hi, is it possible to make a plane reflect light but be invisible in render (camera?).

I am trying to render out an model on an backplate with an HDR Sky and Sun as light, but it gets to dark under/inside. I need to add some light there.

[face_off]

I doubt know if this would work - but try attaching a Polygon Side node to the Opacity pin of the backplate material - so has 0 opacity on one side, and 1 opacity on the other.

Paul