The process of creating photo-realistic 3D models is based on photogrammetry, which is the technique of taking multiple overlapping aerial photographs and deriving measurements from them to create 3D models of objects or scenes. This is done by external systems which generate 3D models in one of the following formats:
DEM (DTM / DSM)
The Valhalla route service (a.k.a. turn-by-turn) is an open-source routing service that lets you integrate routing and navigation into a web or mobile application. The service works globally, and provides dynamic and customizable routing by driving, walking, bicycling, and using multimodal and transit options, with clear directions for maneuvers along the route.
Raster Overview
Vector Overview