Asymptote is a powerful descriptive 2D and 3D vector graphics language for technical drawing, inspired by MetaPost but with an improved C++-like syntax. It provides for figures the same high-quality level of typesetting that LaTeX does for scientific text. Asymptote is a programming language as opposed to just a graphics program. It can exploit the best features of script (command-driven) and graphical user interface (GUI) methods. High-level graphics commands are implemented in the language itself, allowing them to be easily tailored to specific applications.
VisIt is an interactive parallel visualization and graphical analysis tool for viewing scientific data. Users can quickly generate visualizations from their data, animate them through time, manipulate them, and save the resulting images for presentations. VisIt contains a rich set of visualization features so that you can view your data in a variety of ways. It can be used to visualize scalar and vector fields defined on two- and three-dimensional (2D and 3D) structured and unstructured meshes. It was designed to interactively handle very large data set sizes in the terascale range, and works well down to small data sets in the kilobyte range.
Evolvotron is an interactive "generative art" application to evolve images/textures/patterns through an iterative process of random mutation and user-selection driven evolution. If you like lava lamps, and never got tired of the Mandelbrot set, this could be the software for you. It's implemented using Qt, and is multithreaded.
The GNU Triangulated Surface Library (GTS) provides a set of useful functions to deal with 3D surfaces meshed with interconnected triangles. It features metric operations (area, volume, curvature, etc.), 2D Delaunay and constrained Delaunay triangulations, robust geometric predicates and set operations on surfaces (union, intersection, etc.), surface refinement and coarsening (multiresolution models), and bounding-boxes trees for collision/intersection detection.
The Python audio processing suite is a module that contains a variety of convenience functions to process audio signals. It can be used to plot spectral analyses of a song across time and to quickly ascertain encoding quality, but the instrumental goal of this suite is to robustly identify duplicated songs, regardless of which album they were released in, encoding quality, or start time.
Overture is an object-oriented code framework for solving partial differential equations. It provides a portable, flexible software development environment for applications that involve the simulation of physical processes in complex moving geometry. Overture is designed for solving problems on a structured grid or a collection of structured grids. In particular, it can use curvilinear grids, adaptive mesh refinement, and the composite overlapping grid method to represent problems involving complex domains with moving components.
JAME is an application for creating fractals and other graphics artifacts. It is written in the Java language, with some native code to accelerate encoding of videos and images. It has a real-time, multi-threaded graphics engine with layers, filters, effects, a lot of formulas, and parameters. JAME supports operations such as continuous zoom of Mandelbrot and Julia sets, rotation, and color shifting. JAME has also advanced features such as networked computation and scripting. You can take photos of your fractals or record movies from your exploration paths. Photos and movies are stored in a database to be rendered in high resolution and exported to a file. JAME can be extended by plug-ins which provide fractals, formulas, filters, effects, and more.