Render elements - shadows

[postPRODUCTIONS]

I'm hoping this is just me being thick but so far I've not managed to find a way to do this.

I have a scene with just one light, casting hard Vray shadows from behind an object like this:



I am trying to save just the shadow information from the rendering, including not just shadows cast onto other objects but also areas which are shadowed by themselves like this:



No matter which options I try, (& I think I've tried all the various render elements options!) the only result I get is like this:



Any ideas how I can get what I need?

Cheers chaps!

[Morbid Angel]

I may have bad news for you. The shadows "cast" from one object to another are called shadows. The shadows cast from object onto it self are called "shading". This isn't limited to what you outlined though, for example if you extrude a bit of the top face of the box it will cast a proper shadow on to it self, but the darker faces will still not get shadow. What you can do though is use something like a raw lighting pass and invert it that would give you more or less a shaded area of the surface. But for that render i think the shader has to be pure white or else you will get "shading" which wont give you clean key.