Imported CAD coordinates are 3 decimals off

[j.aukema]

Hello,

Im trying to aquire coordinates in Revit from a Civil 3D dwg . In revit the n/s and e/w west are 3 decimals off. In civil 3D the coordinates are X = 187455.151 Y = 428817.802, but in revit the are X = 187455151 Y = 428817802. I tried changing the units from m to mm in Civil 3D, but this didnt change anything. 

How can i fix this?

[Pointdump]

Hi @j.aukema,
"...aquire coordinates in Revit from a Civil 3D dwg."
Details please. How are you going about doing this?
Dave

[ChicagoLooper]

Hi @j.aukema 

The Civil3D drawing has coordinates tied into a Known coordinate system such UTM83-ZoneXX meters.

When evaluating the coordinates you've provided the Revit coordinates are 1000X greater than the Civil coordinates. The Civil3D drawing appears to be in METERS while the Revit drawing appears to be millimeters. 

To test this out, select ALL objects in Revit and SCALE them using 0,0 as the base point and a scale factor of 1/1000. Next, COPY all the scaled objects to your clipboard then PASTE the clipboard contents into a brand new, clean Civil3D imperial template. After the paste, and still in Civil3D, turn on Bing Hybrid Map. This is assuming you've assigned the proper projection in the civil DWG. If you don't know which CS the original author used, you'll need to ask him then assign it.

<<Note: You must assign the proper coordinate system (the drawing's projection) BEFORE turning on Bing Map. You must also be certain which coordinate system the original author used--no guessing allowed. Bing Hybrid Map isn't available (and won't be accurate) if it doesn't have a properly assigned CS.>>

[rl_jackson]

Perhaps this would be of use.

Autodesk Civil 3D Help | Shared Reference Point Extension | Autodesk

https://help.autodesk.com/view/CIV3D/2024/ENU/?guid=Shared_Reference_Point

[j.aukema]

Yes your right. My Civil 3D surface is in meters and Revit is in millimeters. And just like you mentioned my CS is measured in meters (Amersfoort / RD New, this is the main CS used in the Netherlands).

If i change the units in civil 3D to mm using 'dwgunits', the CS units change aswel (from m to mm).  So thats why the're of by a 1000.

The same goes for Revit aswell. I could change the units from mm to m, this would fix the coordinates being displayed wrong. However, i dont want my Revit units in m.

So are there any work-around for this? Is it maybe possible to display coordinate system in meters and the rest in millimeters?

[ChicagoLooper · Accepted solution]

Hi @j.aukema 

<<my CS is measured in meters (Amersfoort / RD New>>

You’re correct. Your drawing will adopt’m drawing units of meters if you choose Amersfoort/RD. Your Revit dwg has drawing units of millimeters which is why you have a scale factor 1000x affecting your coordinates. 

Autodesk doesn’t have an easy-1-button tool to switch from meters to millimeters, but it does have the Shared Reference Point for Civil3D or Revit extension. You’ll need to download the extension and install it in both C3D and Revit. 

Here’s a video from Seiler Design Soultions that demonstrates the extension in an imperial drawing. (You can adjust the instructions for your metric drawing.)  To watch the video click >>HERE<<.