/// <summary>
/// Snap End and Start points for each curve in list 'curves2d' (new point is avarage of both)
/// If found singularity -
/// 1) add index of curve2d after wich need to add singular trim in list 'singulars'
/// 2) snap Start and End points to the corner of surface where Singularity exists
/// </summary>
/// <param name="srf"></param>
/// <param name="curves2d">list of curves in UV projection for sruface 'srf'</param>
/// <param name="singulars">Will contain index of curve2d after which need to add singularity</param>
public static void _SnapCurves2d(this Surface srf, List <NurbsCurve> curves2d, out List <int> singulars)
{
var domainU = srf.Domain(0);
var domainV = srf.Domain(1);
singulars = new List <int>();
for (int i = 0; i < curves2d.Count; i++)
{
int iEnd = i - 1;
int iStart = i;
if (iStart == 0)
{
iEnd = curves2d.Count - 1;
}
var pointStart = new SurfacePoint(curves2d[iStart].PointAtStart);
var pointEnd = new SurfacePoint(curves2d[iEnd].PointAtEnd);
var diffU = Math.Abs(pointStart.u - pointEnd.u);
var diffV = Math.Abs(pointStart.v - pointEnd.v);
if (diffU < 0.01 * domainU.Length && diffV < 0.01 * domainV.Length)
{
var avarageU = (pointStart.u + pointEnd.u) / 2;
var avarageV = (pointStart.v + pointEnd.v) / 2;
var avaragePoint = new Point3d(avarageU, avarageV, 0);
curves2d[iStart].SetStartPoint(avaragePoint);
curves2d[iEnd].SetEndPoint(avaragePoint);
curves2d[iStart].Points.SetPoint(0, avaragePoint);
curves2d[iEnd].Points.SetPoint(curves2d[iEnd].Points.Count - 1, avaragePoint);
}
else
{
var pointStart3d = srf.PointAt(pointStart.u, pointStart.v);
var pointEnd3d = srf.PointAt(pointEnd.u, pointEnd.v);
var distance3d = pointEnd3d._DistanceTo(pointStart3d);
var isExtremSingularity = distance3d < _Double.ZERO;
var isNormalSingularity = (distance3d < 0.001) &&
(diffU > domainU.Length / 7 || diffV > domainV.Length / 7);
if (isExtremSingularity || isNormalSingularity) // singularity present
{
// round start and end points to mutch surface corner in singularity
var pointAtStart = curves2d[iStart].PointAtStart._RoundToDomain(domainU, domainV);
curves2d[iStart].SetStartPoint(pointAtStart);
var pointAtEnd = curves2d[iEnd].PointAtEnd._RoundToDomain(domainU, domainV);
curves2d[iEnd].SetEndPoint(pointAtEnd);
singulars.Add(iEnd);
}
else
{
throw new Exception("Can't snap Curves2d at index " + i);
}
}
}
singulars.Sort();
}
/// <summary>
/// Get centroid of surface base on avarage 3d points devided by paramter 'divby'.
/// If 'divby' is zero - 'srf.PointAt(uDomain.Mid, vDomain.Mid)' will be returned.
/// </summary>
/// <param name="srf"></param>
/// <param name="loopEdges">all edges of loop</param>
/// <param name="accurate">Accurate takes more time but have great precision.</param>
/// <returns></returns>
public static Point3d _GetCentroid(this Surface srf, Curve[] loopEdges, bool accurate)
{
// Get edges points
var MAX_EDGE_POINTS = accurate ? 1000 : 500;
var edgesPoints = new List <Point3d>();
var prevPointAtStart = Point3d.Origin;
var prevPointAtEnd = Point3d.Origin;
var edgesLengths = loopEdges.Select(o => o._GetLength_ThreadSafe()).ToList();
var divbyTol = accurate ? 0.01 : 0.1;
var desiredEdgePointsCount = edgesLengths.Sum() / divbyTol;
if (desiredEdgePointsCount > MAX_EDGE_POINTS)
{
divbyTol = edgesLengths.Sum() / MAX_EDGE_POINTS; // limit edge point at approximatelly 1000 points
}
for (var i = 0; i < loopEdges.Length; i++)
{
var edge = loopEdges[i];
var divby = edge._GetDivBy(edgesLengths[i], divbyTol, 0);
Point3d[] points;
if (edge._TryDivideByCount(divby, out points) && points.Length >= 2)
{
var deleteDuplicatePointIndex = -1;// index of point3d that id duplicated for 2 edges (some connection point)
if (edgesPoints.Count != 0)
{
var distToStart = Math.Min(points.First()._DistanceTo(prevPointAtStart), points.First()._DistanceTo(prevPointAtEnd));
var distToEnd = Math.Min(points.Last()._DistanceTo(prevPointAtStart), points.Last()._DistanceTo(prevPointAtEnd));
if (distToStart < distToEnd && distToStart < 0.001)
{
deleteDuplicatePointIndex = edgesPoints.Count;
}
else if (distToEnd < distToStart && distToEnd < 0.001)
{
deleteDuplicatePointIndex = edgesPoints.Count + points.Length - 1;
}
}
edgesPoints.AddRange(points);
// remove duplicate point if such exists - this will increate accuracy
if (deleteDuplicatePointIndex != -1)
{
edgesPoints.RemoveAt(deleteDuplicatePointIndex);
}
prevPointAtStart = points.First(); // remember PointAtStart of last edge
prevPointAtEnd = points.Last(); // remember PointAtStart of last edge
//Layers.Debug.AddPoints(points, Color.Black);
}
}
// Limit edge points to 1000 - speed improvement (we can have here 26000 points what take 3 seconds of time - to much)
int skipp = edgesPoints.Count / MAX_EDGE_POINTS;
if (skipp > 1)
{
var edgesPoints_limited = new List <Point3d>(MAX_EDGE_POINTS * 2);
var i = 0;
while (i < edgesPoints.Count)
{
edgesPoints_limited.Add(edgesPoints[i]);
i += skipp;
}
edgesPoints = edgesPoints_limited;
}
// detect interval where loop is inside - this will make our calculation more accurate for small loops of big surfaces
//var edgesPointsOnSrf = srf._ClosestPoints(edgesPoints);
//var uDomain = new Interval(edgesPointsOnSrf.Select(o => o.u).Min(), edgesPointsOnSrf.Select(o => o.u).Max());
//var vDomain = new Interval(edgesPointsOnSrf.Select(o => o.v).Min(), edgesPointsOnSrf.Select(o => o.v).Max());
var uDomain = srf.Domain(0);
var vDomain = srf.Domain(1);
var iterationNum = 0;
var iterationCentroid = Point3d.Origin;
var domain3dLength = Double.MaxValue;
var iterationsMax = accurate ? 50 : 10;
var iterationDomain3dLengthEnought = accurate ? 0.0001 : 0.001;
while (iterationNum < iterationsMax &&
domain3dLength > iterationDomain3dLengthEnought)
{
// Get srf points
var srfPoints2d = srf._GetDivby2dPoints(4, uDomain, vDomain);
if (srfPoints2d.Length == 0)
{
break;
}
var srfPoints3d = srfPoints2d.Select(o => srf.PointAt(o.u, o.v)).ToArray();
var bestDist_Pow2 = Double.MaxValue;
var best2dPoint = new SurfacePoint(0, 0);
var best3dPoint = Point3d.Origin;
var bestIndex = -1;
domain3dLength = Double.MaxValue;
for (var i = 0; i < srfPoints2d.Length; i++)
{
var p2d = srfPoints2d[i];
var p3d = srfPoints3d[i];
//var summ3dDists_Pow2 = edgesPoints.Select(ep => ep._DistanceTo_Pow2(p3d)).Sum();
double summ3dDists_Pow2 = 0;
for (int k = 0; k < edgesPoints.Count; k++)
{
summ3dDists_Pow2 += p3d._DistanceTo_Pow2(edgesPoints[k]);
}
if (summ3dDists_Pow2 < bestDist_Pow2)
{
bestDist_Pow2 = summ3dDists_Pow2;
best2dPoint = p2d;
best3dPoint = p3d;
bestIndex = i;
}
//Layers.Debug.AddPoint(p3d, Color.Wheat);
}
//Layers.Debug.AddPoint(best3dPoint, Color.Red);
iterationNum++;
iterationCentroid = best3dPoint;
var domainSrfMidPoint = srf.PointAt(uDomain.Mid, vDomain.Mid);
domain3dLength = Math.Min(domain3dLength, domainSrfMidPoint._DistanceTo(srfPoints3d.First()));
domain3dLength = Math.Min(domain3dLength, domainSrfMidPoint._DistanceTo(srf.PointAt(uDomain.T0, vDomain.T1)));
domain3dLength = Math.Min(domain3dLength, domainSrfMidPoint._DistanceTo(srf.PointAt(uDomain.T1, vDomain.T0)));
domain3dLength = Math.Min(domain3dLength, domainSrfMidPoint._DistanceTo(srfPoints3d.Last()));
uDomain = new Interval(best2dPoint.u - uDomain.Length / 4, best2dPoint.u + uDomain.Length / 4);
vDomain = new Interval(best2dPoint.v - vDomain.Length / 4, best2dPoint.v + vDomain.Length / 4);
}
//Layers.Debug.AddTextPoint("_BrepLoop._GetCentroid", iterationCentroid, Color.Red);
return(iterationCentroid);
}