length=sqrt(velocityvec[0]*velocityvec[0]+velocityvec[1]*velocityvec[1]+velocityvec[2]*velocityvec[2]) velocityvec[0]=velocityvec[0]*1000/length velocityvec[1]=velocityvec[1]*1000/length velocityvec[2]=velocityvec[2]*1000/length