2d timber frame drawing with reference plane

Choosing Reference Faces

Now lets apply some of the key concepts of earlier posts. In practical terms, if the imperfect timber we are using has two relatively square surfaces it is easier to imagine that the perfect timber inside begins on these two surfaces(these are the reference faces) and the remaining perfect faces lie within the remaining imperfect timber. If we align the reference faces of the timber with the reference planes of the building then the important dimensions and functions of the building/structure will be "fixed".
Diagram of timber changes after drying

Choosing Reference Faces – Part 2

Once the reference planes are identified it should be fairly simple to identify them on the timber right? You can just pick any face to be the top reference face right? Well No. Picking the correct surface will make laying out joinery simpler, will make the frame stronger, and ensure that the final frame dimensions match the drawing. The essential concept here is to properly match the timber’s natural characteristics (both strength and aesthetic traits) to the requirements previously identified. Timbers, all wood really, have natural strength characteristics that are derived from their growing conditions and how the timber was sawn out of the log.
Live Edge Timber

The Perfect Timber

Part three of Introduction to Square Rule joinery series Back to the Beginning Let’s go back the original issue of what to do with timbers that vary in size and regularity, i.e. dealing with imperfect timbers; a question you might have considered was why not just use "perfect timbers" whose dimensions are known. Some modern timber framers do and these timbers are known as S4S, but the availability and practicality of acquiring these timbers is often cost prohibitive and/or impossible. The difference in material costs between rough sawn and S4S timber could easily be a factor of 4 or more. […]
Laying out a timber

Introduction to Square Rule Joinery

Understanding square rule joinery is a multi-step process that begins with understanding the goal, the obstacles to reaching that goal, the concept that overcomes these obstacles, and finally the implementation that makes the concept a reality. You can’t simply begin cutting joinery without first knowing how and perhaps more importantly why the steps are important. This series is meant as an overview to help conceptualize the process and you may find that going through the steps multiple times sheds even more light on what is a simple but powerful concept.