Resumen: This paper proposes a new approach to define two frequency trigonometric spline curves with interesting shape preserving properties. This construction requires the normalized B-basis of the space U4(Iα)=span{1,cost,sint,cos2t,sin2t} defined on compact intervals Iα=[0,α], where α is a global shape parameter. It will be shown that the normalized B-basis can be regarded as the equivalent in the trigonometric space U4(Iα) to the Bernstein polynomial basis and shares its well-known symmetry properties. In fact, the normalized B-basis functions converge to the Bernstein polynomials as α→0. As a consequence, the convergence of the obtained piecewise trigonometric curves to uniform quartic B-Spline curves will be also shown. The proposed trigonometric spline curves can be used for CAM design, trajectory-generation, data fitting on the sphere and even to define new algebraic-trigonometric Pythagorean-Hodograph curves and their piecewise counterparts allowing the resolution of C(3 Hermite interpolation problems. Idioma: Inglés DOI: 10.3390/sym15112041 Año: 2023 Publicado en: Symmetry 15, 11 (2023), 2041 [17 pp.] ISSN: 2073-8994 Factor impacto JCR: 2.2 (2023) Categ. JCR: MULTIDISCIPLINARY SCIENCES rank: 50 / 134 = 0.373 (2023) - Q2 - T2 Factor impacto CITESCORE: 5.4 - Computer Science (miscellaneous) (Q1) - Mathematics (all) (Q1) - Physics and Astronomy (miscellaneous) (Q1) - Chemistry (miscellaneous) (Q2)