I am using Autodesk Forge to build a web app, I want to get categories, families, and family types in the original revit project. I have researched but all I can get is families that have instances on view. Can I get a family that doesn't have an instance on view?
If all else fails, you can easily access all the data you list using a standard Revit .NET add-in, which you can migrate to and run in the Forge Design Automation for Revit environment.
I discussed this with the development team. They provide a clear, concise and convincing answer: the Model Derivative will only have the families and types in use, not all that are available in the original RVT. This is by design: MD only extracts what’s visible in the model.