Transfer Proportions to Perspective

[Majenkus]

How do you transfer the dimensions of a box into perspective without guessing? For example, in the pic, how would I transfer the 8X9 black box onto the red perspective plane?

http://i223.photobucket.com/albums/dd89/zombiesincorporated/perspectivequestion.jpg

Thanks :)

[fantasyartist]

Look at successful drawing from Andrew Loomis. In the chapter about perspective he explains how to project things in perspective using measuring points etc. If you're not familiar with loomis just google him and you'll be able to find his books. I hope this is what you was looking for.