Wednesday 19 July 2017

Acquiring Revit Project Coordinates

Typical workflow to acquire project coordinates that we use goes something like this:

1: Obtain Civil or Survey CAD file + Link it into Revit Project; this is typically the “Site” project, but can also be the “Main model” if you are not breaking out the Site in a separate file.

2: Move the CAD file into the proper location as it relates to the building; you can rotate, shift up down left right, etc., etc. – Important to note that you are looking to match a specific geodetic elevation associated within the CAD file to your main floor elevation in addition to the location of the building on the site.

3: Acquire the coordinates of the CAD file – now your Revit model coordinates will match the Real World Coordinates that are (mostly) always associated with the survey file.

4: Next, provide your consultants with the Revit file that has acquired the CAD coordinates. Have them link it Center to Center, or something other than Shared coordinates.

5: Locate (move) the Linked model in the correct position, and then acquire its coordinates.

Note: There are often steps that we take to clean-up the CAD file first (ie: locate specific topo lines on an easily identifiable layer so that you can associate the CAD file in elevation relative to Main floor levels, for example).

The best test that we use after we have acquired the coordinates of the CAD file, is to export a CAD file from Revit (be sure to use Shared Coordinates in the export set-up) and then open the survey and xref the Revit export to 0,0,0. The files should align perfectly if everything has been done correctly. 

Thanks to Dan Sawyer for writing this out for me... I get a lot of questions on this process and Dan's my go-too guy.

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