Hello Reviters,

This is a topic i brought up a while ago: how to work with dwg files for starting a project in a way that you could rexport your files from revit with the same 0,0,0 in cad.

The other day I had to set up a project in Revit with dwg files from quantity surveyors. As usual the 0 was miles away from the drawing (8 by 1 million). Now, i applied the method i had developed beforehand:
1. choosing a point near the actual drawing in the cad file which has simple coordinates (no comma).
2. copy the entire drawing into a new cad file with the basis of the chosen point to the 0,0,0 of the new file
3. define the geographic north in revit
3. link the file in revit with the geographic north active in origine by origine mode and then start modeling it in revit

So far, so good. The next day I opened the file and 2 of 3 cad files had flipped orientation. They hadn't flipped into a logic sense - let's say project north or geographic north. No, they just flipped in a deliberate angle. So I was obliged to relink them.

Anyone, has an idea what could have caused the flip ???

Thanks for your helpful comments,