Gmsh is an automatic 3D finite element grid generator with built-in CAD and post-processing facilities. Its design goal is to provide a simple meshing tool with parametric input and advanced visualization capabilities. It is built around four modules: geometry, mesh, solver, and post-processing. The specification of any input to these modules is done either interactively using the graphical user interface (based on FLTK and OpenGL) or in ASCII text files using Gmsh's own scripting language.
K-3D is a 3D modeling, animation, and rendering system for GNU/Linux & Win32. Features include creation and editing of geometry in multiple realtime OpenGL solid, shaded, and texture-mapped views; unlimited undos and redos; complete extensibility at runtime through third-party plugins; animated procedural geometric effects; all parameters animatable through a consistent control-spline based interface; rendering pipeline to Renderman Interface compliant rendering engines; optimization for use with the Aqsis rendering engine, which features solid modelling, true displacement, and user programmable shaders; and support for background and batch rendering.
Moonlight|3D is a modeling and animation tool for three-dimensional art. It currently supports mesh-based modeling. It's a redesign of Moonlight Atelier, formed after Moonlight Atelier/Creator died in 1999/2000. Rendering is done through pluggable backends. It currently supports Sunflow, with support for RenderMan and others in planning.
FreeCAD is a CAx RAD based on OpenCASCADE, Qt4, and Python. It features some key concepts like Macro recording, Workbenches, and the ability to run as a server. It's also platform-independent. It is is fully scriptable and designed to be easily extensible; only the core functionality is embedded into the core libraries, but all further functionality like support of triangle meshes, CAM, FEM, etc. is implemented in extension modules. Normally, such a module is divided into an 'App' part containing the data structures and algorithms and a 'GUI' containing the graphical representation of data structures, dialogs, workbenches, etc.
pythonOCC is a 3D CAD/PLM development library for the Python programming language. It provides 3D hybrid modeling, data exchange (support for the STEP/IGES file format), GUI management support (wxPython, PyQt, python-xlib), parametric modeling, and advanced meshing features. pythonOCC is built upon the OpenCASCADE 3D modeling kernel and the salomegeom and salomesmesh packages. Some high level packages (for parametric modeling, topology, data exchange, webservices, etc.) extend the builtin features of those libraries to enable highly dynamic and modular programming of any CAD application.
SDXF (Stani's DXF) library can generate complex CAD drawings in the DXF format with all kinds of entities, such as 3DFace, Arc, Insert, Circle, Line, Mtext, Point, Polyline, Rectangle (optionally filled), Solid, and Text. They can be structured with Layers, Blocks, Linetypes, Text styles, and Views.
The GTO format's primary usage is storage of static geometric data. The types of data you might find in a GTO file are things like polygonal meshes, various types of subdivision surfaces, NURBS or UBS surfaces, coordinate systems, hierarchies of objects, material bindings, and even images. It is used by film, video, and game production companies to streamline the modeling, animation, rendering, and 3-D paint processes. The distribution includes source code for a RenderMan Procedural plug-in, four Maya plug-ins, a Houdini plug-in, a number of command line tools, a Wavefront .obj parser, and two Python modules for reading, writing, and editing GTO files.
STPsim is an application that simulates and visualizes switches using the Spanning Tree Protocol. It features a GUI to build and control a custom network topology. A VPython frontend visualizes virtual switches and network cables in a 3D environment. To visualize STP-states, switches and ports change colors and captions in real time.
Dice3DS is a set of Pure Python modules for dealing with 3D Studio format (*.3ds) files. It maps 3DS chunks into a hierarchical set of Python objects; it's a lot like how ElementTree works for XML files. Dice3DS requires Python 2.6 or higher and Numpy. Note that it is not a wrapper for lib3ds.
InnerWorld is an experimental landscape generator running inside Blender 3d. The generator can be used for mesh creation and to populate the virtual world with objects. Mesh generation and procedural object placement can be defined by using a graph editor. Different noise sources and operators can be arranged for procedural content creation. Meshes can be generated from Blender's noise functions, FFT synthesizing, and external gray scaled images acting as height fields.