How to project (bake) an environment texture onto a mesh as if from a slide projector? I have an equirectangular texture applied as the environment. I go to the camera view, match the camera's settings and create my mesh so it somewhat matches the objects' shapes in that texture. I unwrap the mesh. 

I deliberately avoid such methods like cutting an image into small pieces and then manually texturing the objects. It's really tedious and time consuming and I have to do tens of these images. Also, the projection, as I've mentioned, is equirectangular, so doing it manually is really not an option.  
How do I project the pixels from that env. texture onto my mesh? (like a slide projector)
One cheap and fast way of doing it is to use The unwrap option &quot;Project from view&quot; Like in this Picture:

This uses your current 3D viewport as to unwrap it 1to1 into the UV image editor. If you align your camera just right it behaves like a Projected Image. I recommend to do this in the orthographic 3D view as well.