CAD origin?

[Anonymous]

Testing AutoCAD import today, I noticed that the 0,0 point of AutoCAD drawing seems to be ignored.

I made a simple CAD file with a single line far away from the 0,0 point. When I link the file into Revit, the ignores the 0,0 point and just places my CAD drawing. The drawing arrive and place the line at the project base point, ignoring the fact that it is millions of kilometres away. I am wondering why the origin is ignored, especially when I try to import origin to origin. Why is my CAD origin totally ignored?? It seems lik the 0,0 is ignored totally and the drawing is place center to center.

I've attached the CAD test file.

[ToanDN]

What did you choose when you link it?  Origin to Origin?  Center to Center?

[RobDraw]

Even more so that AutoCAD, Revit does not like objects great distances from the "origin". I saw a video that explained the concept of origins in Revit quite well, but cannot relocate it at the moment. Revit handles this quite different from AutoCAD, so you cannot expect this kind of one to one relationship.

[SteveKStafford]

Revit wants us to keep our model near the project's own mathematical origin so all calculations are more reliable. The further from the origin elements are the more floating point math issues affect the graphical accuracy of what is displayed. As such Revit overrides the Auto-Origin to Origin positioning setting when a DWG violates its threshold for extents (20 miles).

As such even a single small element very far from the origin will be force to a center to center position...placing it near Revit's own origin. Warning messages usually appear when this happens. User's often choose to suppress these messages (an option on the dialog). Later such a file doesn't appear to generate a warning when Revit disregards the positioning option chosen.

[Anonymous]

Sorry, I did not get the reply because of email problems.

So I did learn that if there is no geometry at the 0,0 it will not be part of the extents of the drawing!

What confused me is that Autodesk dos not tell you that it will ignore your 0,0 if it would make the drawing extent too big. From my understanding, it put it center to center if the extent of the 0,0 is too far away, but does not warn the user, hence my confusion.

Really, Revit should give a warning to the use that it will ignore its explicit input.