Serious Coordinate Conversion Issue

[kkuecker-traffic]

My company has been encountering this issue since we switched to AutoCAD C3D.  We used to work in 2011 and now 2012

We believe it has something to do with the conversion of International Feet to US Survey Feet.

We obtained MicroStation DGN's of alignments we needed to incorportate into our design.  When we attach  the DGN to our DWG it registers to a different point that in the DGN. 

The shift is equal to the conversion of International Foot to US Survey Foot mutliplied by the linear distance from orgin (0,0).  (Using one International Foot equals 0.999998 US Survey Feet)

We have tried different things such as defining the coordinate system in the C3D file before attaching the refernce, and verifing the original MicroStation file was in the correct coordinate. 

We still get a shift in X,Y coordinates.

[Sinc]

---

@AllenJessup wrote:

It may be time for Autodesk to think of issuing a special build of AutoCAD for Civil 3D. There are Map 3D commands that are disabled in Civil 3D because they will muck up the units. AutoCAD built for Civil 3D should be able to handle Survey Feet!

---

My opinion is that not only should US Survey Feet be a REAL unit in core Autocad, but the Coordinate System stuff should also be in core Autocad.  After all, Autodesk has been adding Google Earth functionality to core Autocad, but in a very funky way.  And having units like Parsecs while failing to have units like US Survey Feet is frankly ridiculous.

[Cadguru42]

I wonder if this is related to my problem where a Microstation V7 drawing that is in US Survey Feet is being considered meters when it's imported.  If I use MAPIMPORT there is no problem. If I use the regular import and get that DGN Import Settings dialog the drawing is "converted" from meters to my US survey feet drawing, when no drawing is set to meters in the first place. There is no option to change what the DGN's units are, so I can't use that import method at all.  From what Mr. Funk told me, the regular import dialog for a DGN is always thinking the drawing is a V8 drawing which is always in meters (If I understood correctly).

[kkuecker-traffic]

In MicroStation, you can go to Settings, Design File

these options should be listed:

Format: MU

Master Unit: Survey Feet

Sub Unit: Custom

Accuract:  0.1234

Advanced Settings

Resolution: 1000 per Distance Survey Foot

If the resolution set to 3048 I believe that is where the issue is coming from.  You have to change that in the seed file.   

[Sinc]

So why do some Army Corps drawings convert correctly, while others do not, even in the same project?  Is it errors on the part of the Microstation users?

[wfberry]

Hello Peter Funk !!

Where are you?

[KENNY-SURVEY]

I have a similar question regarding the same issue.  Because of recent restructuring our organization we switched from Eagle point using standard vanilla AutoCAD to Civil 3-D.  But all the old files, which we have thousands of, have the settings in each drawing set up as international feet.  It's quite easy to change each individual drawing to US feet, but is there any way to convert large groups drawings to US feet?  It will take us long time to convert them all and withoutsome batch process. Any Ideas?