.A3S file extension

This is the basic program to work with .A3S extension

Autodesk Showcase

Autodesk Showcase Autodesk 3D Scene File

Autodesk Showcase is a program that allows you to quickly transform 3D CAD models into interactive walk-throughs and presentations, so that you can evaluate aesthetic and design alternatives in real time with peers, constituents and customers. You can import native Revit files and select a specific Revit view for visualization... (more)

The program works with the following extensions: apf, a3e and a3s