Free landscaping rocks*

* There's always a catch!

3D rendered rocks by www.intresto.com.au/ 

Intresto's MD Malcolm lambert is an atmospheric physicist by trade and, whilst building a house in Tasmania, he realised that unprocessed rock was only one tenth of the cost of finished materials such as brick.   Malcolm conceived the idea of using computational power to perform the difficult 3D geometric manipulations required to build with irregular pieces of rock. 

You can download free 3D rendered rocks and much more for use with Sketchup. SketchUp (also known as Trimble SketchUp) is a 3D modelling program for a broad range of applications such as architectural, civil, mechanical, film as well as video game design — and available in free as well as 'professional' versions.   See 3d rocks here: http://sketchup.google.com/3dwarehouse/details?mid=6d8b19cc20da276f75b791738ce5d1e

The program highlights its ease of use,and an online repository of model assemblies (e.g., windows, doors, automobiles, entourage, etc.) known as 3D Warehouse enables designers to locate, download, use and contribute free models. The program includes a drawing layout functionality, allows surface rendering in variable "styles," accommodates third-party "plug-in" programs enabling other capabilities (e.g., near photo realistic rendering) and enables placement of its models within Google Earth