In an epidemiology transmission probability analysis for a medical facility, ray origin points are distributed over a medical facility floor map. Rays are cast from the ray origin points. The cast rays stop upon encountering a physical barrier mapped in the medical facility floor map. An infectious transmission probability map is computed from intersections of the cast rays. At least a portion of the medical facility floor map is displayed on a display, overlaid with the infectious transmission probability map. The distributing, the casting, and the computing are suitably performed by one or more electronic processors.