public static void ShowFaceDirection(TopoDSFace face, Document Document)
{
var p1 = new gpPnt();
var v1 = new gpVec();
var v2 = new gpVec();
var sf = new BRepAdaptorSurface(face, true);
var u = sf.FirstUParameter;
var x = sf.LastUParameter;
if (Precision.IsInfinite(u))
{
u = (Precision.IsInfinite(x)) ? 0.0 : x;
}
else if (!Precision.IsInfinite(x))
{
u = (u + x) / 2.0;
}
var v = sf.FirstVParameter;
x = sf.LastVParameter;
if (Precision.IsInfinite(v))
{
v = (Precision.IsInfinite(x)) ? 0.0 : x;
}
else if (!Precision.IsInfinite(x))
{
v = (v + x) / 2.0;
}
sf.D1(u, v, p1, v1, v2);
var vector = v1.Crossed(v2);
x = vector.Magnitude;
// The direction vector length
const double length = 70.0;
if (x > 0.0000001)
{
vector.Multiply(length / x);
}
else
{
vector.SetCoord(length / 2.0, 0, 0);
}
var p2 = new gpPnt(p1.X, p1.Y, p1.Z);
p2.Translate(vector);
if (p1.IsEqual(p2, Precision.Confusion))
{
return;
}
DrawArrow(Document, p1, p2, face.Orientation());
}