# Designing Modern Fiddles

I have chosen not to simply copy old instruments.  My method is to develop the profile using the best current understanding of of the methods of the old masters.  While I use a three dimensional CAD system, it is still accomplished by a series of arcs as an old master would have done with compass and divider.  Since the work is three dimensional, I can develop an entire wire-frame of the fiddle.  This allows me to rotate the image in true perspective and "fiddle" with it until it is pleasing from all points of view.

The arching is developed using a modified figure-of-revolution using a nonuniform rational B spline (NURBS) surface.  The easiest way to understand the approach is to think of a simple shell such as a dome. Flatten it by pushing down.  Pinch it in the middle so it looks like a figure eight from above.  Shrink the upper lobe a bit while expanding the lower.  Suddenly, it it looks awfully like a violin.  Mathematically, the profile of this shape is defined by a cosine function and is smooth in all directions.  Interestingly, this function also appears to describe the difference in stiffness of the wood along the grain as compared to across the grain.  The sections are a dead fit to the surviving templates from many of the old masters, particularly Stradivari and Guarneri.

Once the wire-frame is satisfactory, flesh can be put on the bones by fitting isoline NURBS to the profile and arching.  After fitting the isolines the fully meshed plate can be used for FEA if so desired.  The isolines are used to develop a set of templates to guide the carving process.

The result of these operations is a fiddle that is both beautiful, even in tone and sonorous.  Interestingly, the design of these fiddles bear a strong resemblance to those of Stradivari's so-called "Golden Period" which probably reflects my taste in violins rather than any re-discovered secret in my method.  After all, it is the eye of maker controlling the process rather than the process controlling the maker.