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Construction idea Construction drawings Iso line drawings
  2D construktion drawings Explaining of 3D congruence
  3D construktion drawings Calculated 3D with "equal width";
  Outerline design Calculated 3D for a real violin shape model
    Stradivarius iso lines measured by Möckel
    Guarneri del Gesu iso lines measured by Möckel
    Sacconi "belly" iso lines
    Sacconi "back" iso lines

Construction drawings

The plane (2D) geometric development step by step

Step 1 - The square 

The construction starts with a square in which an equilateral triangle is drawn.

Step 2 - The base line

The "Base line" is constructed which dicides the length of the instrument, 6/8 of the original square size (B)

Step 3 - The double base line layout 

The whole figure is doubled by the mirror image through the horizontal square axis.

Step 4 - The extended cords 

The centre in the original square is the rotation point (C) for the next step.

(D) is the extention line of the cords through the intersections of the baseline and triangles.

Step 5 - The final (2D) layout after a determinate rotation 

The complete plane layout occurs when rotations are carried out on the main figures one clockwise and the other counter clockwise.

The rotation stops on the point of intersection (E)

Step 6 - The string lengths and measures appear 

Connecting the midpoints of the side of the equilateral triangles (F), belonging to the size of the baseline radius, points out the position of the bridge on the longitudinal axis in the center. The double string lengths occur (G) when this point and the point of the extended cords intersect with the longitudinal axis. Halve this lengths is the string lengths. At the same time the division between neck and body H and I is decided.

H and I are in 2:3 relationship

Step 7 - Location of corners and smallest width 

The corners of the outline are positioned on the circular arc (K) wHich is drawn from the centre of the original square through the point of intersection (L) of base-line and cord-line.

The smallest width appear between the circular arcs of the rotated base lines (J)

Step 8 - Fingerboard dimension 

The size and proportion of the fingerboard relates as:

when 2xM=650 Than M=325.
If O=24 and the length of the fingerboard 269 mm
Then P=43.86

Step 9 - F-hole size and location  

The position of the F-holes are decided by the Lengths (R) of the side of the equilateral triangle deciding the size of the radius of the base line and its position after the rotation completed rotation

The length (Q) is almost 72 mm

Step 10 - Bass bar location

The irrational direction of the bass-bar is defined by a line (S) from the point of intersection of the cords on the longitudinal axis and the tangent point on the upper F-hole edge


The solid (3D) geometric construction step by step

Step A

The height of the arch is decided by the size of an equilateral triangle and the size of a circular arc equal to a side of the triangle

I = the centre of the original square

II = the height of the arch

Step B

The longitudinal arc is constructed as follows.

Arc III is equal to arch II in step A. The longitudional arc is constructed as predicted the line IV giving the arc center at VI as being a perpendicular line (V) from the center of IV intersecting the transverse axis of the original square at VI

Step C 

Any desired transverse crosssection can be constructed here showing the places of intersection on the widest places between the base line arcs and ther points of intersection between base line and cordline VII, IIX, IX and X

The design process of the outline (none geometric)

  Step D

XI is the shape of a special cross section determined by the 3D geometry.

XII, XIII, XIV show possible scoop arangements to be determent by the violin maker.

It's the choice of the violin maker that determines the shape of the out line.

Step E

Drawing an outer contour line of both upper and lower parts the line almost forms an equilateral triangle with the geometric layout lines that are part of the 2D construction.

Using these "triangles" the design becomes balanced between upper and lower part.

Step F

The circle through the original square and intersection points with the "base line" are useful to locate the corners as well as the inwardly turned "base line" to predict the "waist line"