API for Autodesk Design Review 2018
@Anonymous I been down this road with Autodesk, they no longer develop this product. This includes the ActiveX viewer control. They stopped developing it many years ago and went the way of the cloud. They are now mainly focused on web-based applications. I fought with them for many months on this very subject until a developer pulled me aside and explained it to me. Since they no longer support or update the API for this software, our company went the way of the PDF. We use a control called Foxit Active X SDK PDF Viewer control for our VB/C# .net desktop applications development. Foxit's support and API are very good for their control.
If you look at the properties window of the DesignReview.exe file for 2018 located here: "C:\Program Files (x86)\Autodesk\Autodesk Design Review". You will see that the copyright date is 2011. Which means they have not improved it since then. I figured this out years ago when we switched over to Foxit.
Good luck and feel free to contact me if you need some information on what to do next.
To sgwilliams. We use our developed software as a fast browser/viewer for all our drawings. DWF files are automatically created when Autodesk Inventor saving the drawings and other data related to the drawings is written to SQL Server. The browser shows everything on one screen. All in one 
We have been using it for years. It's much faster than using Autodewsk Vault.
When the Autodesk Design Review 2018 appeared, I also expected the upgrade of the API documentation. Unfortunately this did not happen. I have not even read any information from Autodesk on this subject yet. It is sad.
Thanks for your suggestion to use PDF, maybe this will happen. I was also thinking about saving JPG/PNG, no more software would be needed. For quick preview, it would be enough. We'll see.