public static Curve Flatten3dCurveOnPlane(Curve c, Plane plane)
{
XYZ meanPt = null;
List <XYZ> orderedEigenvectors;
XYZ normal;
if (c is HermiteSpline)
{
var hs = c as HermiteSpline;
if (plane == null)
{
plane = GetPlaneFromCurve(c, false);
}
var projPoints = new List <XYZ>();
foreach (var pt in hs.ControlPoints)
{
var proj = pt - (pt - plane.Origin).DotProduct(plane.Normal) * plane.Normal;
projPoints.Add(proj);
}
return(dynRevitSettings.Revit.Application.Create.NewHermiteSpline(projPoints, false));
}
if (c is NurbSpline)
{
var ns = c as NurbSpline;
BestFitLine.PrincipalComponentsAnalysis(ns.CtrlPoints.ToList(), out meanPt, out orderedEigenvectors);
normal = orderedEigenvectors[0].CrossProduct(orderedEigenvectors[1]).Normalize();
if (plane == null)
{
plane = dynRevitSettings.Doc.Application.Application.Create.NewPlane(normal, meanPt);
}
var projPoints = new List <XYZ>();
foreach (var pt in ns.CtrlPoints)
{
var proj = pt - (pt - plane.Origin).DotProduct(plane.Normal) * plane.Normal;
projPoints.Add(proj);
}
return(dynRevitSettings.Revit.Application.Create.NewNurbSpline(projPoints, ns.Weights, ns.Knots, ns.Degree, ns.isClosed, ns.isRational));
}
return(c);
}
public static Plane GetPlaneFromCurve(Curve c, bool planarOnly)
{
//cases to handle
//straight line - normal will be inconclusive
//find the plane of the curve and generate a sketch plane
double period = c.IsBound ? 0.0 : (c.IsCyclic ? c.Period : 1.0);
var p0 = c.IsBound ? c.Evaluate(0.0, true) : c.Evaluate(0.0, false);
var p1 = c.IsBound ? c.Evaluate(0.5, true) : c.Evaluate(0.25 * period, false);
var p2 = c.IsBound ? c.Evaluate(1.0, true) : c.Evaluate(0.5 * period, false);
if (c is Line)
{
var v1 = p1 - p0;
var v2 = p2 - p0;
XYZ norm = null;
//keep old plane computations
if (Math.Abs(p0.Z - p2.Z) < 0.0001)
{
norm = XYZ.BasisZ;
}
else
{
var p3 = new XYZ(p2.X, p2.Y, p0.Z);
var v3 = p3 - p0;
norm = v1.CrossProduct(v3);
if (norm.IsZeroLength())
{
norm = v2.CrossProduct(XYZ.BasisY);
}
norm = norm.Normalize();
}
return(new Plane(norm, p0));
}
CurveLoop cLoop = new CurveLoop();
cLoop.Append(c.Clone());
if (cLoop.HasPlane())
{
return(cLoop.GetPlane());
}
if (planarOnly)
{
return(null);
}
IList <XYZ> points = c.Tessellate();
List <XYZ> xyzs = new List <XYZ>();
for (int iPoint = 0; iPoint < points.Count; iPoint++)
{
xyzs.Add(points[iPoint]);
}
//var v1 = p1 - p0;
//var v2 = p2 - p0;
//var norm = v1.CrossProduct(v2).Normalize();
////Normal can be zero length in the case of a straight line
////or a curve whose three parameter points as measured above
////happen to lie along the same line. In this case, project
////the last point down to a plane and use the projected vector
////and one of the vectors from above to calculate a normal.
//if (norm.IsZeroLength())
//{
// if (p0.Z == p2.Z)
// {
// norm = XYZ.BasisZ;
// }
// else
// {
// var p3 = new XYZ(p2.X, p2.Y, p0.Z);
// var v3 = p3 - p0;
// norm = v1.CrossProduct(v3);
// }
//}
//var curvePlane = new Plane(norm, p0);
XYZ meanPt;
List <XYZ> orderedEigenvectors;
BestFitLine.PrincipalComponentsAnalysis(xyzs, out meanPt, out orderedEigenvectors);
var normal = orderedEigenvectors[0].CrossProduct(orderedEigenvectors[1]);
var plane = dynRevitSettings.Doc.Application.Application.Create.NewPlane(normal, meanPt);
return(plane);
}