/// <summary>
/// 输出标准STL(ASCII)格式
/// </summary>
/// <returns></returns>
public override string ToString()
{
string normalLine = "facet normal " + Normal.ToString() + "\n";
string outLoopLine = "outer loop" + "\n";
string p1Line = "vertex " + P1.ToXYZString() + "\n";
string p2Line = "vertex " + P2.ToXYZString() + "\n";
string p3Line = "vertex " + P3.ToXYZString() + "\n";
string endLoopLine = "endloop" + "\n";
string endFacet = "endfacet" + "\n";
return(normalLine + outLoopLine + p1Line + p2Line + p3Line + endLoopLine + endFacet);
}
