Revit uses 2 coordinate systems: the measurement coordinate system and the project coordinate system.
[Revit Tutorial] About the coordinate system The measurement coordinate system provides a real-world relational environment for the building model and aims to describe the position on the earth's surface.
[Revit Tutorial] About the coordinate system The project coordinate system describes the position relative to the building model, using the attribute boundary or the selected point in the project scope as a reference, and using this to measure the distance and position the object relative to the model.
[Revit Tutorial] About the coordinate system
The origin of the internal coordinate system provides the basis for the measurement and project coordinate system.
You can also use the shared coordinate system to position the imported or linked model relative to the Revit model.
Measurement coordinate system
Use the measurement coordinate system to identify the specific location of your Revit model on the surface of the earth. This coordinate system is defined outside the context of the project.
Many measurement coordinate systems have been standardized. Some systems use latitude and longitude, while others use XYZ coordinates. The scale handled by the measurement coordinate system is much larger than that handled by the project coordinate system, and it can deal with issues such as the curvature of the earth and topography, which are of no importance to the project coordinate system.
In Revit, the measurement point [Revit Tutorial] about the coordinate system will identify the real-world position near the model. For example, you can place the measurement point at a corner of the project site or the intersection of two attribute lines, and specify its real-world coordinates. (Please refer to the [Revit Tutorial] in the above image about the coordinate system.)
The measurement coordinate system has the same meaning as the terms used in the following other software applications or associated environments:
Global coordinate
GIS coordinates
Raster coordinates
Measurement coordinates
Projected coordinates
National plane
Shared coordinates
Project coordinate system
Use the project coordinate system to determine the position of the project relative to the specified point near the model. This coordinate system is specific to the current project.
In Revit, the origin of the project coordinate system is the project base point [Revit Tutorial] About the coordinate system. Many teams use the project base point as a reference point to make measurements on the site, and place them on the corners of the building or other suitable locations in the model to simplify on-site measurements. (Please refer to the [Revit Tutorial] in the above image about the coordinate system.)
Revit's project coordinate system has the same meaning as the terms used in the following other software applications or associated environments:
Local Coordinates
World Coordinate System (WCS)
World Coordinates (in DWG environment)
User Coordinate System (UCS)
User Coordinates
Design Coordinates
Model Coordinates
Engineering Coordinates
Internal Coordinates
CAD Coordinates