Conversion from Revit to OBJ is not supported yet :(

Revit

A .rvt file a three-dimensional model created by Autodesk’s Revit. Revit is a building information modeling (BIM) program that is used to create 3D building designs for floor plans, elevations and sections. It offers complete project lifecyle from conceptual design till fabrication and construction.

OBJ

OBJ is a geometry definition file format (.obj extension) first developed by Wavefront Technologies for its Advanced Visualizer animation package.

The OBJ file format is a simple data-format that represents 3D geometry alone — namely, the position of each vertex, the UV position of each texture coordinate vertex, vertex normals, and the faces that make each polygon defined as a list of vertices, and texture vertices.

Vertices are stored in a counter-clockwise order by default, making explicit declaration of face normals unnecessary. OBJ coordinates have no units, but OBJ files can contain scale information in a human readable comment line.