If you walk around the furniture wing of an art museum like Philly, you quickly see that similar pieces have all the variety of the human body. But like the human body, the differences are subtle variations of the same basic shape.
Leonardo Da Vinci started his work with a few basic proportion rules. He split the body into 6 or 8 equal parts vertically. He superimposed a grid system based on his dissections, direct observations, and observations of ancient sculptures. These represented a baseline from which his self portrait or the mona lisa was done.
Philadelphia has several of Thomas Eakins drawings that he did as preparation for his paintings. The drawings are carefully, almost draftsmansly done, indicating fader points, horizon lines, reflections etc. Do the finished paintings (which are adjacent to the studies) perfectly match the drawing? Of course not.
The basic proportions establish the composition of the work. Anybody who thinks they can just wing it is....well...let's put it this way John; One's work will improve if one uses the classical proportions. I don't think you have to hold to the dimensions to the third decimal place. And it's just silly to think that because we don't see that level of accuracy on 18th c furniture that no rules were used.
For my part, until I get to be a better artist than Da Vinci, I'm going to stick with some sort of classical proportioning scheme.
Adam
