Put away the abacus, Hoss—here's a Visual Construction Calculator for your proportional processing ponderances
Old drawings exist that lay out proportions for architectural assemblies that are scale-able to build visually pleasing millwork assemblies of any size. These drawings are called Classical Orders of Architecture.
Orders of Architecture are like rules-of-thumb.
There are Greek Orders and Roman Orders. The Tuscan Order is a Roman Order of Architecture, and it is depicted in the drawing below. Brent Hull used the drawing to illustrate How to Design Crown Moldings that are proportionally correct, I will use it as a base for a 'Visual Construction Calculator' in Sketchup.
Dimensions are proportional to column diameter (D), so all molding dimensions (base crown, etc) are a fraction or multiple of D.
Back in the day, when they built using post and beam construction, I assume that the column diameter was the first dimension determined—to make sure the column could support loads that would bear on them.
But for determining the molding treatment for a wall, ceiling height, is the starting point—usually eight, nine, or ten feet.
This creates a computational challenge because the Tuscan order determines the total height as a factor of the column's diameter (D). We need to begin with a ceiling height and reverse engineer for D, so that we can solve for molding sizes defined as fractions or multiples of D.
This could take significant fingers and toes—even using a calculator, but by creating a SketchUp model, you can scale proportional dimensions for ANY 'ceiling height' and have accurate sizes for various trim elements—a.k.a., a Visual Construction Calculator!
Download the model from the Sketchup Wharehouse
—Matt Jackson is a master carpenter, remodeler, SketchUp Wiz, YouTuber, and contributing editor to ProTradeCraft. He lives and works in Rapid City, South Dakota.