Blinn shader - opacity

Hi guys,
so I'm doing video shots out of a single photo shot, and I've stumbled upon a problem whilst creating a window.
I've taken a still photo of a building, removed one of the windows in Photoshop, put in place a rectangle generated within Fusion and added Blinn shader to it to make it opaque. Behind the "glass" i've put a SpotLight shining right on it and added Shake modifier to its Intensity so to create an effect of a Candle Light behind inside the building. The problem is, the light projected on to the window is "trapped" on the side on which the Light Source is directed to - it's not transfered onto the outside of the window. The quick fix would be to put the light source on the outside of the building but I want the same light source to project the light onto the other window in the same room.
Any ideas?

Btw. what is the difference between the Alpha and Opacity in the Blinn node?

Just out of curiosity: why not do all of this in Fusion? Removing a window is easy enough.
Also: why use 3D? You can use 2D tools to achieve what you're after and since your source is 2D it should work fine that way. Doing this in 3D doesn't make this easier.

Just out of curiosity: why not do all of this in Fusion? Removing a window is easy enough.
Also: why use 3D? You can use 2D tools to achieve what you're after and since your source is 2D it should work fine that way. Doing this in 3D doesn't make this easier.

So I am doing most of my modeling in Cinema 4D but I don't know how to bring textures from C4D to Fusion. In my other post, someone suggested I could recreate those textures in Fusion using Blinn node.

What do you mean I could easily do the same in a 2D environment?

In your original post you never mentioned Cinema 4D, only that you were working from a photo (a 2D image) and that you cut out something using Photoshop (a 2D program) so I didn't know any 3D was involved, that's why I said you could do it in 2D.