Author Description

With support from the Defense Modeling and Simulation Office and the National Imagery and Mapping Agency's (NIMA) Terrain Modeling Program Office, the Digital Mapping, Charting, and Geodesy Analysis Program (DMAP) has investigated an extension to NIMA's current Vector Product Format (VPF) that would benefit the Modeling and Simulation community. In its current form, VPF's winged-edge topology is documented as not being capable of modeling a wide range of three-dimensional (3D) objects that may be transmitted and received through the Synthetic Environment Data Representation and Interchange Specification (SEDRIS). This range of objects includes non-manifold objects found in integrated, 3D synthetic environments. DMAP therefore proposes VPF+, an extension to VPF that provides for georelational modeling in 3D and that is SEDRIS capable. VPF+ adds a new level of topology called Level 4 Full 3D topology (Level 4). The topological information encompasses the adjacencies involved in 3D manifold and non-manifold objects, and is described using a new, extended Winged-Edge data structure. This data structure is referred to as "Non- Manifold 3D Winged-Edge Topology." Level 4 also adds a new 3D_Object feature class that is intended to capture a wide range of 3D objects. These features are further defined to be either Well Formed or Not Well Formed, with Well Formed 3D_Object features having additional optional topological information to improve software performance. Finally, Level 4 implements no changes that alter VPF's Level 0 through Level 3 topology.