More precisely, a representation will not represent an object that does not correspond to a solid. These issues may be contradictory with each other. For efficiency purpose, a curvilinear solid may be approximated by a polyhedron. In this case, the curvilinear nature is approximated with polygons. For example, given two curvilinear solids that are tangent to each other, this tangency may disappear after converting to a polyhedron.
Problems occur even for the polyhedra world.
In summary, designing representations for solids is a difficult job and compromises are often necessary. This course will only introduce to you wireframes , boundary representations and constructive solid geometry .