well one way to obtain a shadow material like in 3d studio to simulate my 4 balls image is this : 1 - place on scene plane conformed with the background and all the objects you want 2 - in render panel choise multipass-render and flag and save the shadow option on rendering panel and save as .bmp 3 - now delete the plane and rendering objects and background without shadow, and save it 4 - use a paint program like photoshop on photopaint and apply the shadow render on the normal render 5 - voilall the shadow go on background and with a little bit of opacity you can made great results...