2011 London Dormer #4

Testing the secret line theories on the 2011 London Dormer task model. It works correctly, but would require a 10' x 10' drawing board.

The secret line defines the lower claw angles on rotated purlin rafters. This line is the "Intersection of the Purlin Rafter Run Line & Hip Rafter Claw Line". Drawing a perpendicular from the Secret Line defines the intersection point on the profile drawing of the rotated purlin rafter for the lower claw angle on the rotated purlin rafter. The upper claw angle is defined by the intersection of the hip rafter run line and the DP line.