Import ACAD Dwg./coordinates

[ford347]

I have a dwg I wish to import, but when I do, the drawing is coming in 'off-axis', like it is rotated in ACAD. When I open the Acad file, the file is not rotated? When I rotate it in Revit, then start to place girds over the (e) drawing grids, Revit warns me that my grid is slightly off axis. THis is a big problem because my warped roof system, all my structural components etc., start acting crazy if I'm off axis. So; #1, why is the Acad drawing coming in rotated when it is not rotated in Acad itself, and #2, how do I fix it and get it rotated to 90deg., so Revit doesnt' give me the off-axis error.

I have done this for 3 other projects so far from the same Arch. firm and have not ran into this problem. I just upgraded my Acad version to 2007, maybe that has something to do with it? Some help would be much appreciated! Thanks. Keep in mind I don't know much about Acad.

Josh

[sbrown]

there is probably a usc in the autocad file rotating it to what looks horizontal. If you bump up the decimal places in your dimensions you will find its not truely square, this is a huge issue to be aware of. Autocad lets people draw poorly, so if they drew a wall at 89.99 to another instead of 90, its no big deal, in revit this is a huge problem.

[Steve_Stafford]

Josh,

Related to what Scott said, open the cad file in AutoCAD, go to the View menu > 3D Views > Plan Views > World UCS or Tools > New UCS > World. Either one will orient your cad file according to the world coordinate system of AutoCAD which is what Revit uses when it imports the file. Most likely you'll find, as Scott says, that the building is rotated like Revit is displaying it.

In Revit you can either rotate the cad file so you can draw model your building using project North or change the cadd file itself so it lands horizontally when you import it. The key will be to make sure the rotation is done accurately either in Acad or Revit AND to make sure that most of the linework in the cadd file you want to rely on is also drawn accurately relative to each other. If it isn't draw accurately over the top using it only as a reference, picking the information you can trust.

Then again you could talk to the source of the files about their condition and ask them to tweak them first?

[ford347]

Thanks a lot you guys. I don't think I would have got that alone. I hate to say it, but I wish I new more about Acad so that when I do have to work with other's files, I could do it a little easier.

Thanks again.

Josh