Using Carapace 2 to make perspective guides
There is a little free program called Carapace 2 which was made by Warren Marshall. Warren developed the tool while working at Epic games. The program can be downloaded in the description if you visit the video below on YouTube.
With Carapace you can make perspective guides for drawing. It is a useful tool for concept art and Illustration. I used it to make perspective guides from my rough 3D block outs last year working on The Adventures of Wolf and Hood.
Here is a short video where I demonstrate the tool:
The only thing I found that is worth mentioning is that the density of the grids is controlled by the up and down arrow keys on the keyboard. Also it is worth using Alt and Backspace if you want to start over and redraw the trace lines (resets them properly again).
Other than those notes, all the help for usage is written into the program and can be accessed by pressing F1.