Post, Frits H.Klok, FopkeA.A.G. Requicha2015-09-292015-09-2919861017-4656https://doi.org/10.2312/eg.19861009Deformations, such as bending, twisting and tapering, are important operations for modifying the shape of solid objects. In this paper, we present methods to deform objects defined by sweeping. A closed 2D polygon (the contour) moves along a 3D polyline (the trajectory), thus producing a polygonal approximation of a generalized cylinder. During sweeping, the contour can be incrementally scaled and rotated, resulting in tapered and twisted objects. Also, smoothly bent objects can be produced by performing local rounding operations on trajectories. The methods have been implemented in the solid modeller PLAMO, in which the deformed sweep objects can be used, as well as other types of bodies, as primitives in a CSG tree.10.2312/eg.19861009