work / artifact illustration

Abermagwr Roman Bronze Patera, Coll. Ceredigion Museum 

drawn at 1:1 with constructional geometry, Rorik Smith, 2011

 

The circles represent the ruler and compass construction necessary to arrive at the different sizes of curve in the design of the patera.

Taking the dotted circle of the main bowl in the base view as the starting point, the following assertions can be made, 

The overall length of the patera is one and three quarters the diameter of the bowl.

The pommel has a radius equal to the side of a square whose diagonal is one quarter the diameter of the bowl.
The two handle centers are on the line which intersects the second and third iterations of the bowl along it's main axis.
The section of the base in the side view lies on a circle whose radius is equal to the diameter of the bowl.
The sides of the bowl have centers on a line parallel to the top of the bowl set at a distance apart equal to the radius of the bowl, and at a perpendicular distance equal to the radius of the pommel,
the width of decorative band seen in the side view is defined in the course of establishing the centres for the sides.
The radus of the sides in the side view, from the established centers is equal to the distance between the handle centers and the intersection of the end of the pommel and the main axis in the base view.

Mesolithic worked wood, BCVMS24L2

Hampshire & Wight Trust for Maritime Archaeology Drawn at 1:1, Rorik Smith, 2007​