Here is a list of software available for free. I hope this list is useful. Please add a comment if you come across a free software that can be used in the AEC industry.
Autodesk DWG Trueview: View, Print and Convert any version of Autodesk DWG files.
Autodesk Design Review: View, Print and Markup DWF files.
Autodesk Revit viewer: This is the full blown Revit software. To view and print Revit files you DON’T need a license. However, after making any changes, you need a license to print or save.
Sketchup Home use: Amazing modelling software
Blender: Animation software similar to 3DS Max
Gimp: Amazing image editing software
Open Office: similar to MS Office
PDF Creator : Creates, appends PDF files.
Jing – screen / video capture tool
Historic Urban Modeler
Freeconference call: Most probably for non-commercial use.
Winmerge: Display differences and merge files and directories.
eraser: secure data removal tool for windows
Added based on visitor comments:
Skype: Online chatting / file sharing / desktop sharing…