Say if you're drawing a scene from life (with a viewfinder) of buildings or whatever, do you take into consideration technical perspective (such as VPs and horizon) or rely on the angles, negative/positive space, etc to draw the landscape.
Obviously you'd rely a lot on technical perspective for stuff from imagination, I'm wondering if life reference doesn't require too much perspective practice.
Full, serious answer:
When working from life, it's unusual to actually plot out vanishing points and orthogonals, especially because most vanishing points will lie well outside the picture's dimensions. However, being aware of the techniques of perspective construction allows one's observations and sight measuring to be much more accurate and efficient, and there are situations, as David mentioned, where limited use of linear construction may be more practical than simply sighting. Even when constructing linear perspective from life, the usual procedure is to start with a rough, freehand observational drawing and construct the perspective over that, rather than beginning with the grid.
Well that makes sense. I felt it a little strange to have to locate vanishing points or essentially approach life perspective in a technical perspective structure form given that the information is already 'there' amongst angles/space.