[quote user="Jan Slegr"]It seems there is a lack of knowledge how MicroStation variables works and also how MicroStation application works.[/quote]
No argument here. I have been working through tutorials on Learn Server, but have a ways to go.
[quote user="Jan Slegr"]To import a model from another deign file is a standard MicroStation feature. What is the reason to duplicate it?[/quote]
As I read your reply, I realize that perhaps a MicroStation addin is more than what I need to do in order to satisfy the requirements. Basically, we have a cloud storage platform that contains uploaded .dgn files and a separate design-environment-independent companion application. In response to the user making a choice in that application, I need to download the file to the local disk (not MicroStation-specific) and trigger the built-in, standard MicroStation model import feature on a running instance with an active .dgn file.
My original thought was to load an addin with a timer that would poll the other application for insert commands and execute them as it received them. But if there is a more MicroStation way to pass a standard command or keyin into a running instance of MicroStation, that would be even better, and wouldn't even have to be C#.