It actually is very hard to get the perfect ANGLE when trying to show short distances. I would say use a stick rule, or a 1 foot or 3 foot ruler. They are flat, and can lay down without curvature of a standard tape measure. But no matter what, you can't show the measurements at EACH end at the same time accurately if the item is more than 3 or 4 inches. It gets worse as the item gets longer. You can only show one side accurately at a time. At least that's what it seems to me. So you have to show the finished distance, and hope for the best.. D