public static bool TrianglePlane(Triangle3D t, Plane3D plane, out Line3D intersect)
{
var abLine = new Line3D(t.A, t.B);
var acLine = new Line3D(t.A, t.C);
var bcLine = new Line3D(t.B, t.C);
if (plane.IntersectLine(abLine, out var abIntersect))
{
if (plane.IntersectLine(acLine, out var acIntersect))
{
intersect = new Line3D(
abLine.PointAt(abIntersect),
acLine.PointAt(acIntersect));
return(true);
}
else if (plane.IntersectLine(bcLine, out var bcIntersect))
{
intersect = new Line3D(
abLine.PointAt(abIntersect),
bcLine.PointAt(bcIntersect));
return(true);
}
else
{
intersect = new Line3D();
return(false);
}
}
else if (plane.IntersectLine(bcLine, out var bcIntersect))
{
if (plane.IntersectLine(acLine, out var acIntersect))
{
intersect = new Line3D(
bcLine.PointAt(bcIntersect),
acLine.PointAt(acIntersect));
return(true);
}
else
{
throw new ArgumentException("triangle appears invalid");
}
}
else
{
intersect = new Line3D();
return(false);
}
}
public Arrow3D(Vector3d p1, Vector3d p2, Vector3d normal)
{
this.u = new Vector3d(p1);
this.v = new Vector3d(p2);
// triangle
double d = (p2 - p1).Length() / 10;
d = Math.Max(d, min_dcap);
d = Math.Min(d, max_dcap);
Vector3d lineDir = (p2 - p1).normalize();
Vector3d c = p2 - lineDir * d;
Vector3d dir = normal.Cross(lineDir).normalize();
dir = normal;
if (double.IsNaN(dir.x) || double.IsNaN(dir.y) || double.IsNaN(dir.z))
{
dir = normal.Cross(lineDir).normalize();
}
double d2 = d * 0.6;
Vector3d v1 = c + dir * d2;
Vector3d v2 = c - dir * d2;
this.cap = new Triangle3D(v1, p2, v2);
}