A drawing technique in which you compare the angles of the sides of a triangle formed by three points on your drawing with the same triangle on the subject. This results in accurate proportions. It is the single most important drawing technique to learn.
Course unit: Drawing 2
Recommended further reading
This is my recommended text book for drawing to accompany the VAA curriculum. I am fully in agreement with Wei Xu, the author of this book, that most of the other popular books on drawing will actually lead you in the wrong direction. Therefore I strongly recommend his book.