line sphere

例句：

1. 1.The line sphere is used to represent the boundary of a region in a 3D model.
   线球用于表示三维模型中区域的边界。
2. 2. The line sphere is also used to calculate the volume of a solid object.
   线球还用于计算固体物体的体积。
3. 3. The line sphere is used to represent the center of mass of a system.
   线球用于表示系统的质心。