void serialize(PrintWriter out) {
Cave3DVector dp = p2.minus(p1);
out.format(
"S %d %d %d %d %d %.3f %.3f %.3f\n",
mCnt,
p1.mCnt,
p2.mCnt,
((t1 == null) ? "-1" : t1.mCnt),
((t2 == null) ? "-1" : t2.mCnt),
dp.x,
dp.y,
dp.z);
}
void computeU12() {
u12 = p2.minus(p1);
u12.normalized();
}