Thanks Aoktar! Yes, Earlier on the background was at a different angle and I felt the need to add a plane. However, like you said, it does not need additional geometry - was still wondering why it displayed the weird alpha channel result.

Thanks so much! I've attached a .zip file here.

Hi Aoktar, Thanks for this. However, it appears I'm not allowed to upload a c4d file though?

Hi, Can someone tell me why there's a transparency/alpha grid here? I tried to apply a shadow catcher onto a plane (a) that the gun is 'resting' on.. Behind the plane and the gun model is another plane (b) with a material (holding .jpg pillow photo) applied. instead of the plane(a) going transparent ...