This paper is concerned with a potential-based modeling of three-dimensional workspace for path planning purpose. It is assumed that the workspace boundary is uniformly distributed with generalized charge. The potential at a distance from a point charge is inversely proportional to the distance to the power of an integer. The approach completely eliminates the possibility of the collision between two objects. Potential functions due to polyhedral surfaces are derived analytically. The continuity and differentiability properties of a particular potential function are investigated. Application of such a model in skeletonization of 3D regions is discussed.