Saturday, November 1, 2008

Revit and Navisworks - the issue Shared coordinates

I ran into this problem several times. The strange thing is when you link Revit files and use Shared coordinates it all seems to work fine. Even, exporting to AutoCAD gives you the right coordinates if you set the Export options to Shared properly!
However, when exporting to NavisWorks using the NWC exporter the coordinates are handled in a strange way....

How is this possible? I figured this out...

First of all, let's start with a good Shared Coordinate Revit file (see another post of me, click here). So, in this way I am sure that it is a coorect file.

Next to this imagine the following: besides the Shared Coordinate Origin there is also a Revit Origin. And most of the times the latter give the problems!


To test the whole thing, I created an AutoCAD drawing with an AutoCAD block set on the WCS origin and a block put on the project location.

Next I created a Revit project with an Origin family.
By using an imported AutoCAD DWG (origin-to-origin) that has on the WCS an AutoCAD Block located, I am sure about the origin location in Revit.

I exported this using the NavisWorks exporter to a NWC file. Opened it in NavisWorks and also append the AutoCAD DWG file. They match in NavisWorks. I mean, the WCS from the AutoCAD DWG and the Revit origin from the RVT-project are on the same location. Great!

But now, I will use the method (Shared Coordinates) as descibed in a previous post.
So in Revit, the AutoCAD Project location is placed on top of the Revit origin by moving it. After that by using acquire, the right coordinates are used in Revit. After exporting this to NavisWorks the Revit origin appears on the WCS of the DWG and not on the project location!

So, there it is. When exporting to NavisWorks the export uses the Revit internal origin instead of the Shared coordinates. So, keep that in mind when you are using Revit together with other CAD-applications

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