Summary formula: For example, a 45-degree elbow, you just need to remember this sentence to know how to do it. "Climb 45 degrees, the bridge height is multiplied by 0.8, and the three lines are divided into a bend. The hypotenuse is the climbing height multiplied by 1.4 1.30 degrees, the bridge height multiplied by 0.8 divided by 45 multiplied by 30, and the three lines are divided into a bend. The sloping side is the climbing height multiplied by 2, the horizontal 90-degree bend is the bridge width multiplied by 0.8 bisector, and the sloping side (inside) is more than 600 and 200 times 1.4 1.600 less than 100 times 1.465438 ".