Louis Mazerolle's Planche 7 dévers

Back to square one with Louis Mazerolle's book, Traite Theorique Et Pratique De Charpente for dévers.

dévers --> Rafter Tilted/Canted/Rotated from Plumb


In this drawing I've developed the DP & TC lines for dévers de pas. I don't think the TC line is necessary for the dévers de pas line of the hip rafter. The hip rafter in this drawing is Tilted/Canted/Rotated from Plumb. It's rotated in plan view to the hip rafter backing triangle, H1-H-H2. Once the hip rafter foot print is developed in plan view the DP line, dévers de pas line, follows the footprint of the hip rafter. Then it's a matter of swinging arc's to develop the point Q that defines the hip rafter slope when it's tilted from plumb.

Angle K-D-F' = Hip Rafter Slope Angle for a plumb hip rafter.

Angle K-F-P = Hip Rafter Tilt from plumb.

Point Q is developed by swinging an arc with radius D-F' with center point D and an arc with radius P-F with center point P. The intersection of the two arcs define point Q that defines the Hip Rafter Slope Angle for dévers/canted/tilted/rotated rafter out of plumb.

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Point 'P' is the intersection of the Line Perpendicular to the Hip Rafter Run Line and the DP Line.
That Follows the Footprint of the Hip Rafter.