How to render with a transparent background!

[fhenaux]

Hello, Would anyone know how I can render an object (like a chair) on a transparent background and also keep the shadows as if there was a ground plane? I have managed to render the chair with a transparent background but can't figure out how to keep the shadows as well!

Many thanks
F

[Rich O Brien]

Doesn't Vray render out numerous channels as passes? Shadows and Object ID pass for example?