Free structural models software for linux

Misfit Model 3D is an OpenGL-based 3D model editor that works with triangle-based models. Misfit Model 3D supports multi-level undo, skeletal animations, simple texturing, scripting, command-line batch processing, and a plugin system for adding new model and image filters.
Complete online help is included. It is designed to be easy to use and easy to extend with plugins and scripts.
Misfit Model 3D was written and tested on Linux (2.4 and 2.6 kernels) and has been compiled and tested on most major Linux distributions.
It is not endian-safe so it is unlikely to run on non-x86 hardware platforms--this will probably not change soon unless I get requests for a version thats usable on big-endian archs.
Enhancements:
- The menus have been re-organized. There is a new command to make normals face outward. The texture coordinate window now has a rotate tool. Material support for COB has been improved. Many animation bugs have been fixed. A "File | Export" command has been added to indicate which formats have less reliable write support.

Vertex 3D Model Assembler project is a polygon-based live-end modeller.

The Vertex 3D Model Assembler is a 3D modeller geared towards making high performance models for games and other live-end requirements.

It uses the V3D format to maximize efficiency with OpenGL rendering, and can view/edit any V3D hybrid data.

QML (Quantity Modeling Language) is a "thing"-based language for scientific and mathematical data modeling.
Each "thing" is a quantity which may be associated with either a structure or physical phenomena.
Quantities, in turn, may hold other Quantities or values (numbers or strings). Higher-level data models, which associate or define meanings to various quantities (such as velocity or position), can be built from QML quantities.
The higher-level data model (XML) schema that inherits from QML may be understood, and its instance documents may be parsed into QML documents and objects by the QMLReader.
Enhancements:
- This release adds partial Xerces2 DOM support, and works with Java 1.4 and Java 1.5 (no JAXP DocumentBuilder/Factory support currently).
- The test procedure is a little less chatty.
- Support has been added for testing either/both Crimson/Xerces DOM support.
- (Note: Crimson support only works with Java 1.4, as Java 1.5 interfaces have DOM lvl 2 and 3, which crimson doesnt support).
- This release adds compilerargs, and better build support for different configurations to build.xml.

TBFirewall provides a front-end for ipchains or iptables.

TBFirewall is a front-end created to control firewall rules. Its config files are constructed in the form of tables.

TBFirewall is designed to connect one or more local networks to another, forming an internetwork, but it can also run without problem in other network models.

JSBSim Flight Dynamics Model is an open source flight dynamics model (FDM) that compiles and runs under many operating systems, including Linux, Apple Macintosh, Microsoft Windows, Linux, IRIX, Cygwin (Unix on Windows), etc.
The FDM is essentially the physics/math model that defines the movement of an aircraft under the forces and moments applied to it using the various control mechanisms and from the forces of nature.
JSBSim has no native graphics. It can be run by itself as a standalone program, taking input from a script file and various aircraft configuration files; or, it can be run as an integrated part of a larger flight simulator implementation that includes a visual system.
The most notable example of the use of JSBSim is currently seen in the open source FlightGear simulator. JSBSim models the aerodynamic forces and moments by the classic coefficient buildup method.
JSBSim has seen the growth of a fairly large user base, with some of the more notable projects (of which I am aware) described on the Users page.
Main features:
- Fully configurable flight control system, aerodynamics, propulsion, landing gear arrangement, etc. through XML-based text file format.
- Rotational earth effects on the equations of motion (coriolis and centrifugal acceleration modeled).
- Configurable data output formats to screen, file, socket, or any combination of those.
Enhancements:
- This release includes new options for the standalone JSBSim executable, including improved real-time capability.
- This release also includes experimental (but tested) logic to reduce ground reactions jitter while on the ground.

Gretl is a cross-platform software package for econometric analysis, written in the C programming language. It is is free, open-source software.
You may redistribute it and/or modify it under the terms of the GNU General Public License (GPL) as published by the Free Software Foundation.
Main features:
- Easy intuitive interface (now in French, Italian, Spanish, Polish and German as well as English)
- A wide variety of least-squares based estimators, including two-stage least squares and nonlinear least squares
- Single commands to launch things like augmented Dickey-Fuller test, Chow test for structural stability, Vector Autoregressions, ARMA estimation
- Output models as LaTeX files, in tabular or equation format
- Integrated scripting language: enter commands either via the gui or via script
- Command loop structure for Monte Carlo simulations and iterative estimation procedures
- GUI controller for fine-tuning Gnuplot graphs
- Link to GNU R for further data analysis