Sweep representation is simply turning a 2D object to a 3D object by by sweeping a 2D object over a path. For example, a 2D rectangle moved in a linear path results in the formation of cuboid. To get a better overview of what sweep representation is, lets check the demo below. You can see a small ring but when you sweep it in a circular path using the slider, it leads to the formation of toroid shape. Similarly, we can form cylinder using translational sweep of a circle, prism using a translational sweep of a triangle.
Constructive solid geometry allows a modeler to create a complex surface or object by using Boolean operators to combine simpler objects, potentially generating visually complex objects by combining a few primitive ones. In 3D computer graphics and CAD, CSG is often used in procedural modeling. CSG can also be performed on polygonal meshes, and may or may not be procedural and/or parametric An object is constructed from primitives by means of allowable operations, which are typically Boolean operations on sets: union, intersection and difference, as well as geometric transformations of those sets. Here, in the demo given below, change the primitive meshes and the CSG operation and analyze the changes in the output mesh.