If you have been programming with Revit APIs you probably already know what we are going to do since the process is very similar to Debugging Revit APIs in Visual Studio Express.

Just follow the article How to Debug/Run Navisworks 2013 API Programs, if you are using an Express version of Visual Studio you won’t be able to set a “Start external program” action from within the program. But with a simple workaround you can obtain the same result.

1. Locate the .csproj file of the project you are working on
2. Edit it in a text file editor
3. Before each </PropertyGroup> tag relevant to your scope add the following:

<StartAction>Program</StartAction>
<StartProgram>C:\Program Files\Autodesk\Navisworks Manage 2014\Roamer.exe</StartProgram>
<StartArguments>PATH TO YOUR NWF FILE TO BE OPENED AUTOMATICALLY (optional)</StartArguments>

Eventually adjust the path to the Roamer.exe file, and you’re ready to go!