Revit 2018 – Geo Location Grid Coordinates from AutoCAD

In this short post I wanted to present a new key feature for the coordination of AutoCAD based data such as AutoCAD Civil 3D to Revit. AutoCAD has been able to utilise Bing mapping services to capture mapping and allow the coordination with many different coordinate systems since AutoCAD 2013.

Revit 2018 now supports this workflow by allowing consistent setting out between civil, structural and architectural disciplines using differing platforms.

AutoCAD to Revit - GEOLOCATION

If you have not used this feature within AutoCAD the process is shown below. The Set Location tool is found on the Insert Ribbon or you can type GEOGRAPHICLOCATION on the command line.  This can be set before any geometry is created or you could set this at a later date and then move your geometry to the correct ‘map’ position.

AutoCAD 2018 - Set Location

Once the Geographic Location command is started you can set the desired location marker and then click next.

AutoCAD 2018 - Set Marker

In the next dialog you can set the coordinate system that you want to use. In this case I have used British National Grid (OS) and set the units to millimetres.

AutoCAD 2018 - Coordinate System

Click Next and you then select a point for the location and point up the screen to set true north. Your model is now geolocated and you will see a map in the AutoCAD viewport.

You can now trace site boundaries, roads and any other features that you may require. IN the example below a few existing buildings and the new site are traced.

AutoCAD 2018 - New Site marked out

The AutoCAD DWG is then linked into a Revit project. If you are starting a completely new project then you can use acquire coordinates from the manage ribbon which will set the same British National Grid coordinates. If the project is already set up using the same coordinate system then you can simply link the DWG using Auto – By Shared Coordinates and the AutoCAD drawing will ‘land’ in the correct position.

In the image below another AutoCAD drawing is linked in by Auto – By Shared Coordinates.

Link CAD by Shared Coordinates

lawrenceH

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About lawrenceh

I am employed by Excitech, one of the largest Autodesk resellers in the UK, to provide training and other services such as implementation and project support to our clients. The main products I get involved with are Autodesk Revit Structure, Dynamo & Autodesk Inventor. My personal interests include aviation, engineering and walking.
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3 Responses to Revit 2018 – Geo Location Grid Coordinates from AutoCAD

  1. Thanks, Lawrenceh for your post.
    How do you see the project using this new feature?
    I am used to receiving Survey and Civil/Rail CAD file in a UTM or similar Easting and Northing Coordinate systems. We then insist all site CAD data exchanges contain a Site Map Grid. As use Building folk work in Millimeters and not in SI Meter units, we establish a “local site placement origin” (ideally on a Map Grid intersection and record in the BEP) to avoid IEEE754 – Double precision 64-bit floating point rounding errors. This approach provides a proactive audit method to quickly identify errors on geometry translocations. We can add longitude and latitude information to the site location by using Redfearn’s Formula, Grid to Geographic – http://www.ga.gov.au/geodesy/datums/redfearn_grid_to_geo.jsp

    To me, I can see the great future toolset in Revit, when it allows the user to bring in an aerial photo using a Geographic Location command similar to AutoCAD. Maybe that’s a Revit 2019 new feature list! But otherwise, I’m not really clear on how this tool will actually be used. Due to on-site accessory limitations, we have never provided longitude and latitude information; always Easting’s and Northings.
    Thanks for your post again, and looking forward to your thoughts. Do you receive many Civil data with longitude and latitude information, and not Eastings and Northings? If so, are the coordiantes to 8 decimal places (1.11mm of accessory)?

    Cheers Brian

  2. Thanks for your detailed reply…

  3. lawrenceh says:

    Hi Brian,

    Sorry for the delayed reply, I missed you original post. I think this is really intended just for buildings as Revit is not really used to layout rail and roadways. I am not sure if this feature will eventually be incorporated within Revit as Autodesk will probably favour the Infraworks approach to the site layout.

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