I thought I understood Project Basepoint origin?

[mzabritski]

I've always thought that I had a pretty good understanding of shared coordinates, project basepoints and survey points but I'm having a problem that I can't figure out.

We have a project with an established survey point and an established project base point. From the building model, we've been exporting our AutoCAD backgrounds using the project base point. So far so good. We also have a Revit site model that shares the same shared coordinates and survey point. I noticed that it has different project base point and when exporting to AutoCAD, the dwg 0,0 origin is different than the building backgrounds.

I thought that all I needed to do is in the site model, unclip the project basepoint and move it to the correct location. I did this and everything looks good on the screen. When comparing coordinates between the building and the site, the project basepoint has the same coordinates. However, when I export the site model to DWG using project coordinates, the 0,0 origin of the dwg has not moved. It is still in a random location way to the bottom left of the survey point. I can't seem to get the DWG origin to recognize the project basepoint origin.

Am I doing something wrong? Is this the correct behavior or do I just not fully understand the coordinates?

Thanks

[mzabritski]

I did a bit more reading and now realize that moving the project base point does not allow you to change the 0,0 origin. Looks like I'm out of luck. So, other than actually moving the modeled objects (always a challenge) or using shared coordinates (Can't.. its already established), is there any way to change the 0,0 origin of an exported dwg file?

[JStoney27]

mzabritski,

There are only two options for setting the exported 0,0 point of a CAD file; Shared and Project Internal. Shared refers to the position of the Shared Coordinate. Project Internal is not random, it will reference the Internal Origin (0,0) of the Revit project file. The positions of the shared coordinate, and Project Base Point can be moved around, but the Internal Origin cannot be moved.

You can control the 0,0 location with the Shared Coordinate. You are not limited to just one Shared Coordinate location. If you Select "Location" from the Manage Tab, you can duplicate the current shared location and set it to the current location by selecting "Make Current". Then move the Survey point to whereever you want the 0,0 to be; export using Shared Coordinate. The only real drawback to this is that you cannot "Publish" shared coordinates to another file with more than one location defined.