Groin Vault: Development of Purlin Angles
Section of Vault and Purlin
Tangent to Ellipse and Pitch Angle
The development of a section extracted from a Hip Roof defines a Compound Angle cut on the face of the Purlin set in the plane tangent to the curve at the Framing Point. Given the values of the Saw Miter Angle (Jack Rafter Side Cut Angle) and Saw Blade Bevel Angle (Backing Angle) we can resolve the angles on the face of the Purlin set perpendicular to the plane tangent to the curve at the Framing Point by developing the Purlin Angles on the Stick.
Development of Saw Miter Angle
Development of Saw Blade Bevel Angle
Calculation of Framing Points and Purlin Compound Angles
Compound Angle: Purlin meets Valley

Joe Bartok
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