Just like Autocad a dgn file can have many models - they can be 2d or 3d
They rename the file to .cel and it is a quick way to use that file as a cell library.
I have a masonry.cel file that is nothing but a dgn file with the extension changed (it can be changed back )
They have a utility that will open that .cel file while in a drawing. IT can hold 3d objects or 2d to be used in a fill.
I am trying to import all my masonry 2d cells into a file for Archicad.
It will not recognize the files - they are v8 which has been their version for 20years??? or so.
How do I open or import these libraries.
When we built models to impulate Autocad - this was the way they did models - many 3d models in one file with one model looking at all together. This process would let you work in one model all day or jump to a smaller model for a stair - entry, etc.
In Mstation we would typical have a single file for the Master Model - it woudl be almost empty as it referenced all smaller models into this one. For us the only time we had a model with many models would be for libraries of data