Help / Advice with rendering object on backplate wall

[ShellyAgronin]

Hi all,
I'm trying to render some wired rhombuses on rooms wall.  The rhombuses are 3D and the room is backplate image.
As you can see on attached picture, it doesn't look very realistic because the absence of shadows on the walls.
How can I add the shadows and make the wired rhombuses looked hanged on the wall?
Thank you!

[TpwUK]

Set the white material of the hanging parts to be transparent ?

Martin

[Chad Holton]

I haven't tested this but think it may work: Try creating two planes to act as the wall and apply the ground material to it. Place the rhombuses on planes and if you need to hide any parts of the rhombuses, choose clipping for the ground (wall) material, as it will hide anything under this material. Next, just match up the scene with the backplate.