Cad files rotating....

[STHRevit]

Hi all,

Suddenly had an issue with some of our projects that is quite puzzling. It is a recent development and only in some projects, not all of them.

Using 2010.

We have linked in a cad survey file. The view is set to True North, which suits the survey north direction. (straight up the page).
We then go to our floor plan. Change the view property to "Project North" and then with the "position>rotate project north" rotate the view so the building will be orthogonal to our sheets.

This is great. everything works well. The issue comes when we make some amendments to the cad survey and reload it into the revit file. The cad file rotates further and now does not align properly to either True North or project north!!

Any ideas why this is happening and how we can get it to stop. Like I said before, it is not all of the projects, only some....very annoying.

Please help....

[Scott Womack]

Maybe someone "published" shared coordinates back to the CAD file, possibly after aquiring the shared coordinates from the CAD file? Also, did someone alter the USE in the CAD file, not setting it back to world UCS?

[STHRevit]

Hi Scott,

No, we have checked the UCS in the cad file and all is OK. So I don't think that is it.

We have tried several times with fresh files, and simple cad files (basic rectangles) not publishing or acquiring and it is still happening.

Any other suggestions?

[stephanschneller]

Hi,

I seem to have a similar problem.

Sometimes when I take a job and work on a different computer some of the CAD files 'rotate back' in a different position.

I havent check it but I would say they rotate from project north into true north, which is v. annoying.

Regards,

Stephan

[noah]

I've been having this same problem for years. Lots of searching and no definitive answer. I'm somewhat shocked to finally find someone who describes exactly what I've been experiencing but then the thread goes cold back in 2010. Has nobody figured this out yet?

I just ran another test with a completely dumb simple cad file drawn close to the origin and tried linking with every possible setting and including save the position in the manage links dialog with every possible setting and the cad file always rotates and shifts slightly upon reload. I made no changes to the cad file at all. The only action in Revit was to rotate project north and then reload cad.

Please help!

Thanks,
Noah

[Steve_Stafford]

It sounds like the situation I explain in this BLOG POST might be to blame. The post is the fourth in a series of 4 that demonstrate some shared coordinate concepts.

The most relevant part of the post is this:

"The cause is subtle and simple: it is IMPORTANT to respect the Orientation parameter setting used, in the view that's used, when Acquire Coordinates is used. If you change to the opposite setting and then Reload the link the orientation of the link will change undesirably; regardless of the view you happen to be using during the reload process.

To restate the cause and effect, I used Acquire Coordinates in the Site view while it was assigned to an unnatural orientation setting of Project North. I then changed it to use the more logical True North but AFTER I already used Acquire Coordinates. This means I have to remember to change it back (to Project North) EVERY time before using Reload on the Linked survey file... Or I fix it, which would require resetting the coordinates so I could Acquire Coordinate again with the better settings in place."