No elements were displayed after exporting to STEP AP203/214 format from the File> Export pull down menu, although a .stp file was created.
When selecting Export > STEP AP203/214 the prompt tells you to "Identify element" if there is a single model in your dgn file. If there are multiple elements in the dgn, you should "Select All" so that they will all be exported. Without selecting or identifying any elements in the design file, no elements will get exported.