How to "open" DGN files in headless rhino doc

Rhino Developer
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1

Hi all,

I’m writing a program to consume DGN files in a headless Rhino environment (using Rhino.Inside), and I’ve run into a few limitations.

Specifically, I want to open a DGN file in a headless document while preserving the units of the DGN file, just like opening a file via Rhino’s UI Open command.

Here’s what I’ve discovered so far:

  • RhinoDoc.CreateHeadless(null) + doc.Import(dgnFile) does not preserve the DGN units. Geometry gets scaled to mm (default template units of the headless doc).

  • RhinoDoc.OpenHeadless(path) works exactly as I want for 3dm files, but it can only accept 3dm files :slightly_frowning_face:.

  • FileDgn.Read(path, doc, options) essentially just calls doc.Import, and the FileDgnReadOptions do not expose an “Open” mode or a “ScaleGeometry” option like other file read options do.

Are there any work arounds or methods I’ve missed?

3

Hi Jedd,

I’m looking into this now. Can you point me to the FileReadOptions you speak of when you say, “expose an “Open” mode or a “ScaleGeometry” option like other file read options do”?

Tim

4

Nevermind. I see that it’s part of the base class. I just knew I had never done that in the derived classes I had done for the various file types.

5

If you try something like this does it do what you want?

      FileDgnReadOptions options = new FileDgnReadOptions();
      RhinoDoc mydoc = RhinoDoc.OpenHeadless("C:\\Users\\tim\\Desktop\\MACH001.dgn", options.ToDictionary());

OpenHeadless is overloaded. One takes a archivable dictionary and that will call the appropriate plugin’s ReadFile().

6

Thanks @tim,

This is exactly what I’m looking for.

I think I must have initially dismissed this being a potential option, because the other OpenHeadless overload throws if you call it with anything other than a 3dm extension.