As you probably already know:  Bentley has created a Maxwell Render Exporter that makes it possible to export any 3d scene directly from Microstation to the fantastic render engine Maxwell Render .  Read more about it here:  http://www.maxwellrender.com/ 

IMHO Maxwell is far superior to Microstation when comes to material setup, lighting and photorealistic renderings, - but at the cost of longer render times.  However…