public static NurbsSurface ToRhinoSurface(DB.HermiteFace face, double relativeTolerance)
{
NurbsSurface nurbsSurface = default;
try
{
#if REVIT_2021
using (var surface = DB.ExportUtils.GetNurbsSurfaceDataForSurface(face.GetSurface()))
nurbsSurface = ToRhino(surface, face.GetBoundingBox());
#else
using (var surface = DB.ExportUtils.GetNurbsSurfaceDataForFace(face))
nurbsSurface = ToRhino(surface, face.GetBoundingBox());
#endif
}
catch (Autodesk.Revit.Exceptions.ApplicationException) { }
if (nurbsSurface is null)
{
using (var paramsU = face.get_Params(0))
using (var paramsV = face.get_Params(1))
{
nurbsSurface = FromHermiteSurface
(
paramsU,
paramsV,
face.Points,
face.MixedDerivs,
face.get_Tangents(0),
face.get_Tangents(1)
);
}
}
using (var bboxUV = face.GetBoundingBox())
{
nurbsSurface = nurbsSurface.Trim
(
new Interval(bboxUV.Min.U, bboxUV.Max.U),
new Interval(bboxUV.Min.V, bboxUV.Max.V)
) as NurbsSurface;
}
if (nurbsSurface is object)
{
double ctol = relativeTolerance * Revit.ShortCurveTolerance * 5.0;
if (ctol != 0.0)
{
// Extend using smooth way avoids creating C2 discontinuities
nurbsSurface = nurbsSurface.Extend(IsoStatus.West, ctol, true) as NurbsSurface ?? nurbsSurface;
nurbsSurface = nurbsSurface.Extend(IsoStatus.East, ctol, true) as NurbsSurface ?? nurbsSurface;
nurbsSurface = nurbsSurface.Extend(IsoStatus.South, ctol, true) as NurbsSurface ?? nurbsSurface;
nurbsSurface = nurbsSurface.Extend(IsoStatus.North, ctol, true) as NurbsSurface ?? nurbsSurface;
}
}
return(nurbsSurface);
}
public static NurbsSurface ToRhinoSurface(this DB.HermiteFace face)
{
NurbsSurface nurbsSurface = default;
try
{
using (var surface = DB.ExportUtils.GetNurbsSurfaceDataForFace(face))
nurbsSurface = surface.ToRhino(face.GetBoundingBox());
}
catch (Autodesk.Revit.Exceptions.ApplicationException) { }
if (nurbsSurface is null)
{
nurbsSurface = FromHermiteSurface
(
face.Points,
face.MixedDerivs,
face.get_Params(0).Cast <double>().ToArray(),
face.get_Params(1).Cast <double>().ToArray(),
face.get_Tangents(0),
face.get_Tangents(1)
);
}
if (nurbsSurface is object)
{
double ctol = Revit.ShortCurveTolerance * 5.0;
// Extend using smooth way avoids creating C2 discontinuities
nurbsSurface = nurbsSurface.Extend(IsoStatus.West, ctol, true) as NurbsSurface ?? nurbsSurface;
nurbsSurface = nurbsSurface.Extend(IsoStatus.East, ctol, true) as NurbsSurface ?? nurbsSurface;
nurbsSurface = nurbsSurface.Extend(IsoStatus.South, ctol, true) as NurbsSurface ?? nurbsSurface;
nurbsSurface = nurbsSurface.Extend(IsoStatus.North, ctol, true) as NurbsSurface ?? nurbsSurface;
}
return(nurbsSurface);
}
public static Surface ExtractSurface(Autodesk.Revit.DB.HermiteFace face, IEnumerable <PolyCurve> edgeLoops)
{
// The number of interpolating points in the u direction is given by get_Params
var uParams = face.get_Params(0).Cast <double>().ToArray();
var vParams = face.get_Params(1).Cast <double>().ToArray();
var numU = uParams.Length;
var numV = vParams.Length;
// unpack the points
var points = face.Points;
// structure the points as 2d array - numU x numV
var ptArr = new Autodesk.DesignScript.Geometry.Point[numV][];
var count = 0;
for (var i = 0; i < numV; i++)
{
ptArr[i] = new Autodesk.DesignScript.Geometry.Point[numU];
for (var j = 0; j < numU; j++)
{
ptArr[i][j] = points[count++].ToPoint();
}
}
// unpack the tangents
var uTangents = face.get_Tangents(0);
var vTangents = face.get_Tangents(1);
// structure the tangents as 2d array - numU x numV
var uTangentsArr = new Vector[numV][];
var vTangentsArr = new Vector[numV][];
count = 0;
for (var i = 0; i < numV; i++)
{
uTangentsArr[i] = new Vector[numU];
vTangentsArr[i] = new Vector[numU];
for (var j = 0; j < numU; j++)
{
uTangentsArr[i][j] = uTangents[count].ToVector();
vTangentsArr[i][j] = vTangents[count].ToVector();
count++;
}
}
// u tangents run in increasing column direction
var uStartTangents = uTangentsArr.Select(x => x[0]).ToArray();
var uEndTangents = uTangentsArr.Select(x => x[numU - 1]).ToArray();
// v tangents run in increasing row direction
var vStartTangents = vTangentsArr[0];
var vEndTangents = vTangentsArr[numV - 1];
// The mixed derivs are the twist vectors - dP / dUdV
var md = face.MixedDerivs;
Vector[] mds =
{
md[0].ToVector(),
md[numU - 1].ToVector(),
md[(md.Count - 1) - (numU - 1)].ToVector(),
md[md.Count - 1].ToVector()
};
return(NurbsSurface.ByPointsTangentsKnotsDerivatives(ptArr,
uStartTangents,
uEndTangents,
vStartTangents,
vEndTangents,
HermiteToNurbs.Clamp(uParams),
HermiteToNurbs.Clamp(vParams),
mds));
}