I forget...

[YoyoBoy]

How do you make an object invisible except for the shadows cast onto it? I've done it a few times in the past, but the only thing I can remember is that it wasn't very intuitive.

[Dariusz Makowski (Dadal)]

Apply vray matte shadow to it

[cheerioboy]

dis' ?

right click on object
- vray object properties
. Alpha contribution: -1.0
. Direct light
, Shadows, ticked
, Affect alpha, ticked (optional; depending on how you're going to use it)

[YoyoBoy]

Ah yes! But you have also need to tick "Matte Object." Thanks so much.