Opacity overlay "frontplate"

[PhilippeV8]

I'd like to ask for a "frontplate" with opacity.
That should be possible, right ?

Just the same as the backplate, but one that comes in front of the lot and uses trancparency from the image file (tiff).

This would be most usefull for example, if you have to render an object over a backplate, but there is a tree or anything that sits between the camera and the object.
I could copy the backplate and mask everything out that is NOT going to cover the rendered object.

[PhilippeV8]

Maybe in this way, you might even fake those cloud-shadow-maps from my other thread.

[JonWelch]

Using this Frontplate, would you also be able to receive shadows and reflections of whatever it is you set as the front plate? I like this idea, some of the Environmental Renders I do for my company will have some very shiny plastics or metals and whenever I render using a Backplate I have to use either a decently matching HDRI scene such as a kitchen interior for example. Or I will do some overlaying in Photoshop in the post-processing. So I like this idea if it allows you to give those missing shadows or reflections. Also could work as a DOF shot, applying bluriness to the foreground. Just thinking out loud.