Use shared positioning to maintain relative positions when combining multiple files in a model.
This video demonstrates the following:
When you combine multiple files in a single project, you need to establish the positions of the files in relation to each other. Use the Shared Coordinate tools to establish the relative positions of the different files and ensure that those relationships are maintained. To establish a common coordinate position and then share that position between files, use the Acquire Coordinates tool or the Publish Coordinates tool.
In this example, we have a site survey that was created in AutoCAD. It is a DWG file, consisting of property lines and contour lines. The origin, or 'zero, zero' position, in the DWG file is visible at the lower left corner of the property.
The DWG file is linked into the Revit file. Since shared positioning has not been set up, the site is imported with the origin-to-origin option. To establish a shared coordinate system between the survey DWG and the project, acquire the coordinates of the DWG file. From the Manage tab, select Coordinates, and then select Acquire Coordinates. Now the linked DWG file is selected, and the survey point of the project is moved to the origin of the DWG file. The coordinates are all set to zero, matching the value of the same position in the survey DWG file. The DWG and the project now share a coordinate system. The project base point is unclipped and moved to a position to establish where coordinates relative to the project (not the site) will be measured from.
In cases where you link different buildings, or parts of one building, into a project, instead of acquiring the coordinates from the links, the coordinates of the host project are published to the linked files. The garage in this project is a linked Revit project with its own coordinate system. To share the coordinates of the host file with the garage file, on the Manage tab, select Coordinates, and then select Publish Coordinates. Now the link of the garage is selected. In the Location dialog, click OK. When the host file is saved, a dialog is displayed to inform you that the coordinate positions in the garage file will be changed.
When you open the garage model, the change to the survey point is evident. Now that this file shares coordinates with both the survey DWG file and the host project, either one can be linked with the Shared Coordinates Positioning option to align the files in the correct position.
Using files with shared coordinate systems allows you to link files together to ensure that the relative positions are maintained.