A new kind of quasi-quartic trigonometric polynomial base functions with a shape parameter λ
over the space Ω=span {1, sint, cost, sint2t, cos2t} is presented, and the corresponding quasi-quartic
trigonometric Bézier curves and surfaces are defined by the introduced base functions. The quasi-quartic
trigonometric Bézier curves inherit most of properties similar to those of quartic Bézier curves, and can be
adjusted easily by using the shape parameter λ. The jointing conditions of two pieces of curves with G2 and
C4 continuity are discussed. With the shape parameter chosen properly, the defined curves can express
exactly any plane curves or space curves defined by parametric equation based on{1, sint, cost, sint2t, cos2t}
and circular helix with high degree of accuracy without using rational form. The corresponding tensor
product surfaces can also represent precisely some quadratic surfaces, such as sphere, paraboloid, cylindrical
surfaces, and some complex surfaces. The relationship between quasi-quartic trigonometric Bézier curves
and quartic Bézier curves is also discussed, the larger is parameter λ, and the more approach is the quasi-
quartic trigonometric Bézier curve to the control polygon. Examples are given to illustrate that the curves and
surfaces can be used as an efficient new model for geometric design in the fields of CAGD.