Project coordinates and surveyor's coordinates

In order to position the project correctly in relation to the real environment, and to ensure that the discipline models are placed so that they automatically fit together, they must be placed correctly in the building modeling program. This is done by means of a common zero point. Whether the zero point is the surveyors’ coordinates, or the bottom left grid intersection is not important as long as all parties agree - and preferably has documented this in an ICT specification and/or ICT process manual.

There are differences in how the various building modeling programs handle a zero point that is placed far away from the building, which is often the case with surveyors coordinates in their DWG drawings, where the “World Coordinate” in AutoCADis located many thousands of miles from the building.

In Archicad, this works well, while in Revit you have establish a relationship between the project and the country coordinator using a “Survey Point” object. If this solution is desired in Archicad, a “Survey Point” object is also used.

It is recommended that, regardless of the solution, a single common local zero point which is close to the building, is defined in the project’s ICT specification or ICT process manual, and describes the location of the location (s) of the local zero (s), as seen in the example below.

Revit

Revit operates with three types of coordination points, of which only two are visible:

1. Project Base Point - used as 0,0,0 for the project
2. Survey Point - surveyors’ coordinates that tell where in the world the building is located
3. Origin Point - Inner Base Point in Revit. This point is not visible in the project.

It is advantageous to place all three coordination points in the same place and mark the point with two module lines (x, y).
The location of the building is then coordinated between disciplines and should be located close to Project Base Point.

Link:
https://knowledge.autodesk.com/support/revit-products/learn-explore/caas/simplecontent/content/coordinates-systems-20-miles-limit-the-max-distance-input-part-i.html

In Revit Coordination points can be turned on via the Visibility window. Under the Site category, Project Base Point and Survey Point can be displayed by checking the box.

Two icons appear in the workspace. The circle is Project Base Point, the triangle is Survey Point. All values out of the box are zero. To check if Startup Point is the same point as the other two, it is possible to move Project Base Point to the starting location (original). This can be done by selecting Project Base Point, right-clicking and selecting Move to Startup Location.

When this setting is dimmed, Project Base Point is already at the starting position.

ARCHICAD

The Archicad Project Origin is shown with a black cross in plan view. Here, the surveyors coordinate, or a local, project-specific origin can be located.

If you don’t want the IFC file to use Archicad’s Project Origin, you can instead place a ”Survey Point” object that defines a new origin point for IFC exports:

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