Google’s 3D modeling application Sketchup is what a good tool should be: Intuitive to learn, easy to use and best of all; free!
I’ve found Sketchup to be a huge help in imagining environments and as a guide for drawing. In the example of the visiting hall of Canaleta prison, I had Jorge describe the place for me. From his information I gleaned the approximate dimensions, the open air nature of the room with the chain link fence screens and the benches.
In under an hour I had the room built in Sketchup, using readymade elements such as the chain link and benches from the Sketchup “warehouse“, a user generated depository of items you can download. No sense in building a bench if 3 other people have already done it.

The model of the visiting hall
The purpose of using this tool is not so much the tracing, but the great help in determining “camera angles” when an environment’s relation to the subjects is important. (more…)