xsi5 : composing an object realistically to a photo

Hey there, i need to know how to compose a character onto an image with the shadow interacting to give the impression that the character is in there... can anyone tell me how or to do it.. any pointers are welcome

Thanks

There are tutorials on this topic because it's a long story, but here are some pointers:

1. Create the ground plane and some boxes that represent your main objects and try to align your camera to your photos via rotoscoping. If you have to match a video you will have to use a camera tracking software for this. Example:
Science D Visions 3D Equalizer
2d3 boujou
RealViz Matchmover

2. Model the objects that will receive and cast shadows, you don't need to texture them - they are for shadows only.

3. Configure the passes, you will need the shadow pass where you will render only shadows that will be composited with your 3d objects and background. (Here are some tutorials on this.)

4. Composite all your rendered layers. Use multiply for the shadow pass.

Cheers!