For a spring we use following structure:

typedef struct { int i,j; // points indexes float length; // rest length float nx,ny; // normal vector } CSpring;

In a CSpring structure we keep an index of first (i) and second (j) point. At a level of mesh creation we will also calculate rest length of the spring to use it in a subroutine of linear spring force calculation. Also a normal vector^{4} to the spring will be calculated and kept in a CSpring structure.

Maciej Matyka 2004-03-30