compositing objects - research

The sky has been selected using the magic wand tool. After pressing 'q', I highlighted both the selected and unselected areas to more easily verify if everything was correctly processed. This method proves effective, as it ensures there are no gaps through the images—a potential issue like a window revealing parts of the building behind it.

i can use the quick masking mode i am in to use white and black (including transparency) to make an accurate selection. 

I dragged the masked robot into my plate. with this robot, I didn't want it to be behind the buildings so I added him normally on the top layer. 

i then used the paint tool to make a oval shaped brush to add a quick shadow.