Silo 2 is a focused 3D modeling application with the ability to effortlessly switch between organically sculpting high-polygon models and precisely controlling hard-edged surfaces. It can be used for anything from creating 3D characters for video games and movies to quickly exploring 3D architectural ideas.

Silo is currently being used at top studios worldwide as both a stand-alone design tool and as a versatile element of a multi-software 3D graphics workflow. It is available for both Windows and Mac OS.

Windows version:
System Requirements
-Windows 2000 or newer (for PC) or Mac OS X 10.3 or better
-400 MHz cpu (1 GHz recommended)
-512 MB RAM (1 GB recommended)
-Graphics card supporting 1024 x 768 x 16-bit color and OpenGL (24 or 32 bit color recommended)
-20 MB hard drive space
-Two-button mouse (three-button mouse or two-button mouse with scroll wheel recommended)

http://rapidshare.com/files/144050760/SILO-2.1.1-PRO.rar