What is Terraform?
Terraform is an interactive fractal landscape generator/viewer. It allows you to create fractal terrain (also called a height field) and transform it using a number of algorithms. It is meant to be a tool for those who want to generate digital terrain models for use in raytracing or other simulations. It’s written in C++ using the GTK (actually Gtk–) widget set and as such has a non-sucking graphical user interface.