Description from developers page,
Flow Architect Studio 3D is a software package for design and presentation. It enables you to design and visualize in 3D, any scene you need for example: buildings, interiors, spaces or your products. Flow helps you to present your work to others with screenshots, movies and a 3D real-time virtual walk. Virtual walk is a real-time interactive presentation that can take a form of an application in a single executable file or an O4C file. A visualization in a form of an application can be shown to your clients or audience and shared through a website. An O4C file can be published on a web page with a use of a free O4C Web Browser Plugin or viewed with a free O4C Viewer.
Download here and follow instructions in the readme to install and activate.
To get to the download, be sure to click CONTINUE and NOT Download.