Two different versions of geometry of circular-arc curvilinear shaped teeth gears, commonly known as curvilinear gears, are proposed based on generation by face-milling cutters. These cutters are: (i) a spread-blade cutter that generates simultaneously both sides of the gear tooth surfaces, and (ii) fixed-setting cutters that generate by single-side cutting each side of the gear tooth surfaces. The computerized processes of virtual generation of both members of the gear set are described and algorithms for simulation of meshing, tooth contact analysis, and finite element analysis are applied. Numerical examples of design show the advantages and disadvantages of the proposed two versions of geometry.