cast shadows only on external objects-image w.i.p.

[matteosperi]

Hi; I have a problem..in all renders :)
to underexpose the exterior (even if it's not fiscally correct), I usually create exterior materials and decrease the gamma or exposure value.
If I want to create a plane that generates shadow, how can I make only the exterior materials receive that plane's shadow?
so as not to affect the internal light? it's possible? thank you
Matteo

[maru]

It is not possible to make some specific objects accept shadows only from another specific object(s) if that's what you would like to do.

How about making your window glass material darker but only when seen directly? (it would not affect reflections, refractions, GI, or lighting in general, but anything behind that window would appear darker)

[matteosperi]

ok thanks.. it's an interesting solution and i have to do some tests.
I also thought of two separate renderings .. one external and one internal and then merge them in PS. but the calculation times increase a lot
thanks!!
Matteo