Shadows projected in Ground plane

[JZennio]

Hello!,

My job requires creating scenes with domotic devices in an artificial illumination and postproduced ambient, of course for showing in catalogs, media, etc... I have the same problem, and I don´t know if its solution is easily configurable in Keyshot or not; once I have my touch panel, I add a ground plane which projects shadows, in order to make a postroduction in Photoshop for completing my scene with a bedroom photo or whatever.

The problem is that, in the whole ground plane, the only thing I need is the shadow, so, rest of the plane would be better to have it as trasparent or alpha, to make a clean composition....but I don´t know the way to do it.

I would appreciate some help if  possible, because this fact is very useful for me.

Thank you in advance, and best regards.