Rendering only shadows

I am curious as to whether or not there is a way to render the shadows that are cast by / cast on an object without rendering the objects themselves. At the immediate moment my purpose is to have a character cast a shadow on a plane, but not render the plane, but this would also come in handy when doing post-pro compositing.

To render only the shadow casted on the plane you need to turn on ONLY SHADOW option from the material settings. It’s under the mirror transparency options.

Ah, I knew it was hiding there somewhere. Thanks.

Under the materials buttons->Mirror Transp there is a button called Only shadow. This doesn’t render the object but only the shadows that would fall on it. If you make the object casting the shadow transparent it will still cast shadows unless you have TraShadow selected for the shadow RECIEVING objects.