该代码是一个基于MATLAB语言编辑的四面体有限元长应变四面体算法，包含一个例子很实用，性能稳定。感谢大家的分享。-This code is a kind of constrain Tetrahedral fem compution on MATLAB。there are total code and an example in cube。It is very practical and stable。thank you for your exchanging。

first code written in c++ for generating 3D tetrahedral elements inside unite cube with sphere inside it.