Occasionally I receive a question: “Can we access Collaboration for Revit (C4R) model using Forge API?” The answer is: “not quite, but a partially, yes.” Here is the reason why the answer is not a simple yes or no.
When you are working with C4R, you can see a model on BIM 360 Team. This is actually a “published” model. When Revit model is initially uploaded to the cloud for the first time, and every time you press “Publish Latest” (image below), the system publishes the Revit model to BIM 360 Team. The central file that project members works in work-sharing is stored somewhere else. Using Forge API, you can only access to a model published to BIM 360 Team. If you are interested in the API access to the central file, you cannot do currently. Unfortunately, there is no API to publish to the Team, either.
Accessing a Revit model in BIM 360 Team using Forge API is possible since May, 2016. To make it work, the project must be created after last May and the C4R add-in released around/after that time must be used. Prior to last May, publish was done using a different file storage (S3), while after May, it uses OSS, the same file storage system that we have public Forge APIs. Once you can access to a model, you can use the viewer and extract information programmatically, for example. If you are using Forge, trying to access the existing projects which were created before the last May and API calls are failing, you may want to create a new project and try again. You should be able to access a model in BIM 360 Team using Forge API just like models you uploaded to the Team directly.