There are no decimal points in Geometry

Author Sim Ayers 2020 www.raftertools.com

The Art of the Line for Carpentry
Stereotomy Geometry

This book is a subset of the Holy Grail of Roof Framing Geometry & Trigonometry books.

The book includes step by step instructions on developing stereotomic drawings on Art du Trait de Charpente, Trestles, Tréteau à devers, Canted Trestles, Louis Mozerolles' Joiners Table, Sawhorses, and the Saint Andrews' Cross, twisted crosses. You'll also find theories on hip rafter shift-offset, standard roof framing kernel trait drawings, German Schiften DP-Shadow Line techniques, folding net roof surface and net plane geometric development, when hip rafters collide, the Warlock Cut, and developing upper and lower claws on rafters using Axioms.

I've developed a Trestle Base Geometry drawing that can be used for a combination of trestle drawings with Saint Andrews' Crosses. All of the Saint Andrews' Crosses will be in the same location on the drawings and the cuts on the Saint Andrews' Crosses will be dependent on the rotation of the trestle legs. With this base drawing it can be used for canted trestle legs rotated into the long plan, short plan, with plumb trestle legs, or plumb legs rotated 45° from plumb.

There are 500 plus French art du trait of Charpente and German Schiften Geometry drawings with step by step instructions showing how to develop the Saint Andrews' Cross on the fold- down roof surface. These drawings of developing the Saint Andrews' Cross need to be studied thoroughly before developing the Saint Andrews' Cross on trestles. There are examples of developing the geometry for the Saint Andrews' Crosses on hip rafters plumb to the earth, hip rafters canted into the short plan, hip rafters canted into the long plan, and hip rafters rotated 45° from plumb. These drawings will also allow a carpenter to install the Saint Andrews' Cross on any roof. The roof framing Axioms can also be used on restoration work on buildings built in the middle ages by the monks and Knights of the Templar. Some monasteries and barns built in the middle ages have canted hip rafters with jack rafters that have upper and lower claws. The geometry for these jack rafter claws is fairly simple if you know how to lay out the hip rafter rotated 45° from plumb on to its arris.

The roof framing Axioms can also be used on restoration work on buildings built in the middle ages by the monks and Knights of the Templar. Some monasteries and barns built in the middle ages have canted hip rafters with jack rafters that have upper and lower claws. The geometry for these jack rafter claws is fairly simple if you know how to lay out the hip rafter rotated 45° from plumb on to its arris.

For carpenters participating in the WorldSkills Carpentry Competition, this book is a great starting point. There are hundreds of geometric developments that needed to be studied to compete and drawing out the trestles and jointers table is a great way to get started.

There are 11 Roof Framing Geometry Axioms. However, axiom #1 must be completely understood to use the rest of the axioms.

Axiom #1
All rafters have a DP Line, Devers De Pas Line. The DP line is the line in plan view that follows the vertical plane tilt of the rafter. The DP line can also be the rafter run line for rafters that are plumb to the earth. That have a vertical plane tilt of zero degrees. For all rafters that are plumb to the earth, the DP Line is the same as the rafter run line.

With this axiom, all rafters have a DP Line, it makes the rules of geometry a lot easier to follow. The original use of the term DP refers to the line in plan view that follows the canted plane of the rafter. However, if the term DP is applied to all rafter run lines it allows us to use the same geometric rules that apply to canted rafters apply to rafters that are plumb. Like plumb hip rafters and plumb jack rafters.

Other theories on the French art du trait of Charpente and German Schiften Geometry that need attention:

All the lines in the drawings have a theory for the location of the line. Nothing is drawn at random. Each line will be at an intersection of at least two other lines. There are intersections of level plane lines with plumb lines. Some lines will be drawn through the intersection of two lines, but they are drawn perpendicular to another line in the drawing.

All views are drawn perpendicular to the axis of rotation.

Besides the moonwalk lines in the joiners table drawings, there are the secret lines, director lines, intersecting plane rotation lines, and the die hard line. Just like Bruce Willis shot down the helicopter in the movie Live Free or Die Hard, I felt it was a Yippee-ki-yay, motherfucker moment when I used the spatial part of my brain to draw the last line of geometry in the jointers table task model. Louis Mazerolle was a pure genius laying down the stereotomic lines for the jointers table without the use of a 3d cad drawing. His drawing is just brilliant.

Table Contents

The Art of the Line for Carpentry
Stereotomy Geometry
HG Book III There are no decimal points in Geometry
Roof Framing Geometry Proposition – Axioms
Art du Trait de Charpente
The Art of the Line for Carpentry
Art du Trait de Charpente Basics
Art du Trait de Charpente Basics
Hip & Valley Rafter Shift
Art du Trait de Charpente Basics
Task Model #1
Art du Trait de Charpente Basics
Task Model #2
Art du Trait de Charpente Basics
Trade Secret for Purlins
Art du Trait de Charpente Basics
Study of the cuts for Purlins
Art du Trait de Charpente Basics
Task Model #3
Art du Trait de Charpente Basics
BE - Bottom Edge Plane Geometric Development
Art du Trait de Charpente Basics
Task Model #5
Art du Trait de Charpente Basics
Task Model #6
Art du Trait de Charpente Basics
Task Model #7
Purlin Notch Study
Standard Roof Framing Kernel Trait Drawing
Standard Roof Framing Kernel Line Drawing
Crocodile Header Mortise
Hip Rafter Housing Angle Geometric Development
Hip Rafter Foot Print Geometric Development
DP-Grasshopper Method for Canted Hip Rafters
DP-Shadow Line Geometric Development
Canted Hip Rafter DP-Shadow Line Geometric Development
GrassHopper Geometric Development for Canted Hip Rafter
Canted Rafter DP-Shadow Line Geometric Development
A Bear Needs Its Claws
When Hips Collide
Hip Rafter Rotated 45° From Plumb
Frindsbury Barn in South Eastern England
Hip Rafter Rotated 45° From Plumb
Using German Schiften for Rafter Claws
A Bear Needs Its Claws Using Shiften
Jack Rafter Upper Claw Geometric Development
BE - Bottom Edge Plane Geometric Development
Purlin Upper Claw Geometric Development
Purlin Lower Claw Geometric Development
Net Roof Surface Geometric Development
Plumb Hip Rafter Net Roof Surface Geometric Development
Eave Angle: 90°
Pitch: Unequal
Hip Rafter: Plumb
Jack Rafter: Plumb
Plumb Hip Rafter Net Roof Surface Geometric Development
Eave Angle: 90°
Pitch: Unequal
Hip Rafter: Plumb
Jack Rafter: Plumb
Saint Andrews' Cross:Skewed
Plumb Hip Rafter Net Roof Surface Geometric Development
Eave Angle: 90°
Pitch: Unequal
Hip Rafter: Plumb
Saint Andrews' Cross:Skewed
The roof surface is folded down over plan view
Canted Hip Rafter Net Roof Surface Geometric Development
Eave Angle: 90°
Pitch: Unequal
Hip Rafter: Canted into Short Plan
Jack Rafter: Plumb
Saint Andrews' Cross:Skewed
Canted Hip Rafter Net Roof Surface Geometric Development
Eave Angle: 90°
Pitch: Unequal
Hip Rafter: Canted into Long Plan
Jack Rafter: Plumb
Saint Andrews' Cross:Skewed
Canted Hip Rafter Net Roof Surface Geometric Development
Eave Angle: 70°
Pitch: Unequal
Hip Rafter: Canted
Jack Rafter: Plumb
Canted Hip Rafter Net Roof Surface Geometric Development
Eave Angle: 70°
Pitch: Unequal
Hip Rafter: Canted
Hip Rafter Rotated 45° From Plumb Net Roof Surface Geometric Development
Octagon Roof Framing Geometric Development
Octagon Net Roof Surface Geometric Development
Eave Angle: 135°
Pitch: Equal
Hip Rafter: Plumb
Jack Rafter: Plumb
Cross Brace Purlin Rafter: Skewed
at Eave Line
Hexagon Roof Framing Geometric Development
Hexagon Net Roof Surface Geometric Development
Eave Angle: 120°
Pitch: Equal
Hip Rafter: Plumb
Jack Rafter: Plumb
Cross Brace Purlin Rafter: Skewed
at Eave Line
Pentagon Roof Framing Geometric Development
Pentagon Net Roof Surface Geometric Development
Eave Angle: 108°
Pitch: Equal
Hip Rafter: Plumb
Jack Rafter: Plumb
Cross Brace Purlin Rafter: Skewed
at Eave Line
Sloping Ridge Basic's
Task Model: Sloping Ridges
Aurora Roof Framing Plan Challenge
Aurora Trapezoid Roof Framing Plan Challenge
American Journeyman Carpenters Examination
German Schiften Roof Averaging Exam
Armor Bevels
Armor Bevels for an Unequal Pitched Roof
Rhombicuboctahedron Challenge
Four Legged Trestles, Joiners Table, and the Traveling Cayenne Hexagonal Trestle
The Crawling Feet Trestle
Trait-Carré Relocated
Trestle with All of the Legs Canted into the Long Plan
Trestle with All of the Legs Canted into the Short Plan
Plumb - Arris Trestle
Jobsite Trestle Any Size
Trestles à la carte
Joiners Table : 3 Legged Trestle
Traveling Cayenne Hexagonal Trestle
Twisted Cross Board
Intersecting Rafters using the
Secondary Footprint Lines Technique
Intersecting Plumb Rafters using the
Secondary Footprint Lines Technique
Intersecting Rafters using the
Secondary Footprint Lines Technique
Arris – Arris
Intersecting Rafters using the
Secondary Footprint Lines Technique Plumb-Plumb
Cut Left
Intersecting Rafters using the
Secondary Footprint Lines Technique Arris-Plumb
Cut Left
Intersecting Rafters using the
Secondary Footprint Lines Technique Plumb-Canted
Cut Left
Intersecting Rafters using the
Secondary Footprint Lines Technique Canted-Canted
Cut Left
Intersecting Rafters using the
Secondary Footprint Lines Technique Arris-Canted
Cut Left
Canted Hip & Valley Rafters with Jack Rafter Claws
Layover Valley Sleeper
WorldSkills Carpentry Competition Practice Task Model
Task Model: Canted Cross
Arêtier-à-devers
Hexagon Canted Cross: Dormer Sloping Ridge
Pentagon Canted Cross


The Art of the Line for Carpentry
The Art of the Line for Carpentry
The Art of the Line for Carpentry
The Art of the Line for Carpentry
The Art of the Line for Carpentry

ISBN's