C 开发的有限元软件，界面还可以，不错，可以试试。 FElt is a free system for introductory level finite element analysis. It is primarily intended as a teaching tool for introductory type courses in finite elements - probably in the mechanical/structural/civil fields. I

VB与AUTO CAD联合开发的优化设计软件，优化设计的是一个螺母的开发过程，非常有用。-VB and the joint development of AUTO CAD optimized design software, and optimize the design is a nut of the development process, very useful.

曲线求解的方程，矩阵求解。非常好的东西。在CAD二次开发上可以用到,用ObjectArx- Curve of the equation solving, matrix solving. Very good things. In the secondary development of CAD can be used with ObjectArx