I am regenerating / posting rules to customize shields in fantasy games.
There are several factors that affect the durability, effectiveness, coast, weight and style of shields.
Among these are Size (including thickness), Shape, Strapping / grip, Material, Construction method, Accoutraments (rims / facings), Curvature and Finishes.
Common shield shapes:
Round
Oval
Heater (Think interstate sign with a flat top)
Kite (a narrower elongated heater)
Rectangular
While any combination of properties is possible some historical trends make certain groups of traits more common.
Heater shields are almost always curved and strapped
Center grip (unstrapped) shields are generally round or kite shaped.
Rectangular and oval shields are generally large (Scutum)
To design a shield first choose size. This will determine base figures for Weight, Cost and DR
The material presented here is the original creation of the contributors, intended for use with the GURPS system from Steve Jackson Games. This material is not official and is not endorsed by Steve Jackson Games.