CAD to GeoDatabase - How are Coded Values Assigned relative to DGN Level?

[DavidLight]

I'm trying to better understand how the Cad to GDB conversion works relative especially to Annotation being assigned a Coded Value in the GDB based on level within the DGN. The assignment of the Coded Value seems almost random and this causes issues when attempting to merge data from two very similar but slightly differing DGN layer structure files into one GDB Feature Class. It seems for example that coded value 1 may represent level 60 in one converted GDB Annotation Feature Class and coded value 1 may be assigned to level 11 in another very similar file with the exception that the other DGN file does not have level 60 used or turned on (not sure which at this point). My problem seems to arrive when merging the two File GDB Annotation Feature Classes that have been converted from DGN files). The two files are merged based on the seemingly random assigned coded values that were established during the CAD to GDB conversion instead of honoring the actual DGN level assignments. This produces an output which seems to indicate what we had previously called "Annotation Jumping Levels". I cannot understand how the the CAD to GDB conversion determines the order of level assignments. It would seem to me that the coded value should be matched to the Level... Always without exception. If so, it seems this would eliminate the apparent "Annotation Jumping Levels". Am I missing something??

[AdrianWelsh]

David,

ArcGIS cannot read all of the details of a dgn file, unfortunately. Some important aspects are left out when it converts over, leaving lots of issues.

I know that FME software uses some sort of converting tool that seamlessly takes dgn data and imports it into GIS (in whatever format), but of course, that comes with a subscription cost.

I have not seen the attribute information being really different from one dgn to another when it should be the same. 

What I always see are these attributes from a dgn:

FID. Shape, Entity, Level, Layer, LyrFrzn, LyrOn, Color, Linetype, Elevation, LineWt and RefName.

The "level" in microstation seems to coincide with "layer" in GIS. And mainly only the color, linetype, and linewt are the only things that change for me. The others kind of stay the same or are completely irrelevant.

Can you show some specific examples of what you're seeing and how they're different?

[DavidLight]

Thanks for the reply Adrian.

For a hypothetical example:

Master DGN contains Annotation (and Polylines) levels 3 and 8

Incoming DGN contains Annotation (and Polylines) levels 1, 3, 8, and 11

Both will be converted to Geodatabases called MasterGeoCAD and IncomingGeoCAD respectively.

I need to be able to reliably merge data from IncomingGeoCAD Levels 3 and 8 (I assume: Most likely assigned Coded Values 1 and 2) into MasterGeoCAD levels 3 and 8 (I assume: Most likely assigned Coded Values 0 and 1 respectively).  I think this would INCORRECTLY cause Coded Value 1/Level 3 IncomingGeoCAD data to be assigned to Coded Value 1/Level 8 in the MasterGeoCAD; assuming the values would be merged based on coded values.

*****Does the CAD to GDB tool have the ability to assign Coded value 3 to Level 3, Coded Value 11 to Level 11, etc?  If so, this would be great!  *****

[AdrianWelsh]

David,

That's a tricky one. I don't really use the CAD to GDB tool when using CAD data. My workflow consists of, creating a new project (in Pro), loading a custom coordinate system, loading the CAD data (check to see if it lines up), then exporting the CAD data to a feature class (then running Repair Geometry tool since I usually get some bad geometry).

After that, I have to look at what I have and refer back to the CAD drawing to see what's what. It's a manual process.

For your data, the only thing I could do would be to test your theories and see what's what based on the originating CAD data. From looking at the CAD to GDB tool, there are not many options for looking at coded values. Can you just bring in the raw data real quick and double check to see if your numbers are lining up correctly or see if your theory is true on the coded values?

[DavidLight]

Thanks for the response.  We have been doing the conversions for quite some time and just beginning to identify problems when merging data from very similar CAD files.  The problems do seem to originate from CAD files with an extra layer used which seems to cause re-aligning of the coded values.  Then merges/appends seem to be based on coded values.

[AdrianWelsh]

I too see issues with referenced in CAD layers into original drawings. My CAD people do not like making a "GIS Specific" dgn but I make them do it anyway, haha.