C Specification

This extension allows an application to create a spatial anchor, an arbitrary freespace point in the user’s physical environment that will then be tracked by the runtime. The runtime should then adjust the position and orientation of that anchor’s origin over time as needed, independently of all other spaces and anchors, to ensure that it maintains its original mapping to the real world.



Spatial anchors are often used in combination with an UNBOUNDED_MSFT reference space. UNBOUNDED_MSFT reference spaces adjust their origin as necessary to keep the viewer’s coordinates relative to the space’s origin stable. Such adjustments maintain the visual stability of content currently near the viewer, but may cause content placed far from the viewer to drift in its alignment to the real world by the time the user moves close again. By creating an XrSpatialAnchorMSFT where a piece of content is placed and then always rendering that content relative to its anchor’s space, an application can ensure that each piece of content stays at a fixed location in the environment.

See Also

Document Notes

For more information, see the OpenXR Specification

This page is extracted from the OpenXR Specification. Fixes and changes should be made to the Specification, not directly.

Copyright 2014-2022 The Khronos Group Inc.