GPDes3D is a C++ library for supporting the development of general purpose, discrete-event simulation models. It is aimed at simulation model developers, with a knowledge of C++, on Linux/Unix and Win32 platforms.
KLevel is a heightfield modelling tool designed to mimic Leveller for Windows. It features an OpenGL preview and many brush-like tools.
OpenVL is a framework for handling, processing & visualizing volumetric data (CT, MRI etc). It provides: powerful data access & layout API, plugins for volume processing tasks (image processing, segmentation etc), and support for multiple file-formats.