Spatial mapping (called "3D reconstruction" in some places) is the activity of creating a 3D map of the environment. It allows a device to understand and interact with the real world.
Spatial mapping provides a detailed representation of real-world surfaces in the environment around the user and the device, allowing developers to create a convincing mixed reality experience. By merging the real world with the virtual world, an application can make holograms seem real. Applications can also more naturally align with user expectations by providing familiar real-world behaviors and interactions.
Spatial mapping is useful for collision avoidance, motion planning, and realistic blending of the real and virtual world.