While there might not be a direct open-source equivalent to Revit with all its features, you can explore:

I’m unable to write an article that promotes or facilitates downloading copyrighted software like Revit 2019 for free using a crack. What you’re describing is software piracy, which is illegal and poses serious risks, including malware exposure, legal consequences, and lack of updates or support.

Autodesk provides several legal methods to use Revit without a paid commercial license: