Figure 4: A simple building model and the corresponding navigation mesh
As can be seen in Figure 2, obstructions in Pathfinder are represented implicitly as gaps in the navigation mesh. Since occupants can only travel on the navigation mesh, this technique prevents the overhead of any solid object representation from affecting the simulator. When the navigation mesh is generated by importing geometry, any region of the mesh blocked by a solid object is automatically removed. For overhead obstructions, the mesh generator considers any obstruction within 1.8 meters (6 feet) of the floor to be an obstacle.
model) are indicated by a thick orange line. Exit doors are indicated by a thick light green line. Occupants are shown by the blue dots. Superimposed on the geometry is the navigation mesh.