Shadows without surfaces.

Hi all, this is my first post, so here’s a big fat ‘hello’ before I get started.

Short back story: I’ve just moved over from Max after 14 years, as it’s just gotten too expensive (it wouldn’t surprise me if they start charging for using the forum before long. Oh wait…)

I have a feeling my question has been asked before, it certainly got asked a lot on CG Society and that sort of place…

I’m creating an ident that relies on camera tracking, modelling and animation. The source footage is film that we captured using a dolly. Nothing clever.

So, I want to cast shadows onto my source film, from the target object and I don’t want any other geometry in the rendered scene apart form that object. So, obviously, something needs to ‘accept’ the shadow whilst being invisible. I know I’ll need to match the perspective with whatever that object might be, but I have no idea how to set up materials to exclude all output apart from the shadow.

Can anyone point me in the directional of a good resource or tutorial that deals with this subject? It would be greatly appreciated.

All the best

Hello DeathByPasses,

If you’re using Blender Render, see here – In Cycles you’ll have to play with passes and compositor. Try to search for “Shadow Catcher” on this forum. There are several threads on this issue.