Is there a way to Live Project From View I'm trying to model from an image set as a background.
I have the camera and axis all lined up and I have a cube scaled to fit a building in the image. I Projected From View the front face of the building and it lines up well.
There is an overhang off the front of the building that I would like to extrude off the box and also project from view.

As soon as I modify the geometry the UVs start getting 'wonky' stretching and moving in relation to where loop-cuts were made etc.

Is there a way to have blender constantly projecting from view so that as I'm modeling I can see how the geometry is lining up an adjust accordingly.



Ignore the portion off camera, I'll deal with that later.
If you are sliding vertices, or making loop cuts, make sure that the Correct UV option is enabled.



As an alternative you can use the UV project modifier, and use the camera as projector. That way the texture of the object will not change regardless of the geometry and the shape of the UVs. Once you are done editing the geometry you can make the projection permanent by applying the modifier. 

The camera angle can be matched using the BLAM add-on. For more information see this post: How can I recreate the floor using a photograph?