By John Flanagan
Introduction
Every project has a project base point and a survey point , although they might not be visible in all views, because of visibility settings and view clippings. They cannot be deleted. The project base point defines the origin (0,0,0) of the project coordinate system. It also can be used to position the building on the site and for locating the design elements of a building during construction. Spot coordinates and spot elevations that reference the project coordinate system are displayed relative to this point. The survey point represents a known point in the physical world, such as a geodetic survey marker. The survey point is used to correctly orient the building geometry in another coordinate system, such as the coordinate system used in a civil engineering application.
Fig 1: Visibility Graphic Overrides – Turn on Visibility for Project Base Point & Survey Point
To find the Shared Coordinate System’s Origin:
- Set the icon to unclipped
- Set all values to zero
Fig 2: Survey Point Icon 
The centre of the relocated Survey Point will mark the origin (equivalent to the UCS origin).
In my next blog (Coordinates Part 2), I will cover Acquiring and Publishing Coordinates in Revit Architecture 2017.
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