Frequent tipster Danny Korem shares a tip about how to draw accurately in AutoCAD — without even trying!
"While drafting your linework, don't pay too much attention to accuracy or precision; we'll let AutoCAD take care of that. Once you have completed your geometry, you can AutoConstrain it. All constraints that were selected, and a pair of tolerance values, will do most of the work. Using single constraints will fix it in no time. To set up real-world dimensions, use dimensional constraints. This will stretch the geometry to meet your needs. Finally, use Quick Dim, select the geometry, and choose dim locations."
Notes from Cadalyst Tip Reviewer Brian Benton: AutoCAD 20120 introduced parametric constraints in the form of dimensional and geometric constraints. Constraints force or keep your linework's relationships intact regardless of what you do to it. For example, if two lines are constrained to be parallel, then rotating one line will rotate the other — that's a geometric constraint. Dimensional constraints retain an object's length, radius, or angle. You can turn on Inferred Constraints so that your objects are automatically constrained as you create them.