by Chris Tyler:
Bathroom Ladder, Part 1: How a perpendicular relationship helps the modeling process
This modeling tutorial is designed to address some questions regarding how the active grid functions work. It shows how to effectively use grids and guides to control the modeling process and shows many situations where precise modeling can be achieved by use of custom and standard active grids, in conjunction with guides. The fundamental perpendicular to surface relationship is discussed to give a basic sense for how these modeling tools work. The Bathroom Ladder Tutorial #2, the UV mapping components, is here.