64-bit only.

Autodesk Revit software provides mechanical, electrical
and plumbing (MEP) engineers with the tools to design
even the most complex building systems. Revit supports
Building Information Modeling (BIM), helping you drive
accurate design, analysis, and documentation of more
efficient building systems from concept through to construction.
Use information-rich models to support building systems
design throughout the building lifecycle.

http://www.autodesk.com