//--------------------------------------------------------------------------------------------------
public static bool GetCenteredPlaneFromFace(TopoDS_Face face, out Pln plane)
{
var brepAdaptor = new BRepAdaptor_Surface(face, true);
if (brepAdaptor.GetGeomType() != GeomAbs_SurfaceType.GeomAbs_Plane)
{
Messages.Error("Selected face is not a plane type surface.");
plane = Pln.XOY;
return(false);
}
double centerU = brepAdaptor.FirstUParameter() + (brepAdaptor.LastUParameter() - brepAdaptor.FirstUParameter()) / 2;
double centerV = brepAdaptor.FirstVParameter() + (brepAdaptor.LastVParameter() - brepAdaptor.FirstVParameter()) / 2;
var centerPnt = brepAdaptor.Value(centerU, centerV);
var pos = brepAdaptor.Plane().Position;
var dir = brepAdaptor.Plane().Position.Direction;
if (face.Orientation() == TopAbs_Orientation.TopAbs_REVERSED)
{
dir.Reverse();
}
if (pos.Direction.DotCross(pos.XDirection, pos.YDirection) < 0)
{
dir.Reverse();
}
plane = new Pln(centerPnt, dir);
return(true);
}
/// <summary>
/// triangulate using the opencascade's triangulation
/// </summary>
/// <param name="shape">input shape</param>
/// <param name="deflection">parameter to define the maximum angle</param>
/// <returns>a list of faces</returns>
public List <Face> Triangulation(TopoDS_Shape shape, double deflection)
{
List <Face> faces = new List <Face>();
BRepMesh.BRepMesh_IncrementalMesh im = new BRepMesh.BRepMesh_IncrementalMesh(shape, deflection); // 0.7 it controls the number of triangles
im.Perform();
if (im.IsDone())
{
for (TopExp_Explorer aFaceExplorer = new TopExp_Explorer(im.Shape(), TopAbs_ShapeEnum.TopAbs_FACE); aFaceExplorer.More(); aFaceExplorer.Next())
{
TopoDS_Face face = TopoDS.TopoDS.ToFace(aFaceExplorer.Current());
TopLoc.TopLoc_Location L = new TopLoc.TopLoc_Location();
Poly_Triangulation tri = BRep.BRep_Tool.Triangulation(face, ref L);
bool isDone = true;
if (isDone)
{
Poly_Array1OfTriangle triangles = tri.Triangles();
TColgp_Array1OfPnt nodes = tri.Nodes();
for (int i = tri.Triangles().Lower(); i < tri.Triangles().Upper() + 1; i++)
{
Poly_Triangle triangle = triangles.Value(i);
int node1 = 0, node2 = 0, node3 = 0;
triangle.Get(ref node1, ref node2, ref node3);
gp_Pnt v1 = nodes.Value(node1);
gp_Pnt v2 = nodes.Value(node2);
gp_Pnt v3 = nodes.Value(node3);
// don't forget about face orientation :)
Face f = new Face(new List <gp_Pnt> {
v1, v2, v3
})
{
orientation = face.Orientation()
};
faces.Add(f);
}
}
}
}
mesh = new MyMesh(faces);
return(faces);
}
//--------------------------------------------------------------------------------------------------
/// <summary>
/// Searches for the face of a shape, and find the parallel face, both by area comparison
/// </summary>
public static (TopoDS_Face face, Pln?plane, TopoDS_Face opFace, Pln?opPlane) FindFaceByAreaSize(TopoDS_Shape shape, Func <double, double, bool> comparer)
{
TopoDS_Face foundFace = null;
Pln? foundPlane = null;
TopoDS_Face opFace = null;
Pln? opPlane = null;
// Find the longest face
double faceArea = Double.NaN;
var faceInfos = new List <(TopoDS_Face face, double area, Pln plane)>();
var faces = shape.Faces();
foreach (var face in faces)
{
var brepAdaptor = new BRepAdaptor_Surface(face);
if (brepAdaptor.GetGeomType() != GeomAbs_SurfaceType.GeomAbs_Plane)
{
continue;
}
var area = face.Area();
var plane = brepAdaptor.Plane();
if (face.Orientation() == TopAbs_Orientation.TopAbs_REVERSED)
{
plane.Position.ZReverse();
}
faceInfos.Add((face, area, plane));
if (foundFace != null && foundFace.IsSame(face))
{
// Same edge with another orientation
if (foundFace.Orientation() == TopAbs_Orientation.TopAbs_REVERSED &&
face.Orientation() == TopAbs_Orientation.TopAbs_FORWARD)
{
// Prefer forward edges
foundFace = face;
}
continue;
}
if (foundFace == null || comparer(area, faceArea))
{
foundFace = face;
faceArea = area;
foundPlane = plane;
}
}
if (foundPlane != null)
{
// Find opposite edge
faceArea = Double.NaN;
foreach (var fi in faceInfos)
{
if (ReferenceEquals(fi.face, foundFace))
{
continue;
}
if (!fi.plane.Axis.IsParallel(foundPlane.Value.Axis, 0.00001))
{
continue;
}
if (opFace == null || comparer(fi.area, faceArea))
{
opFace = fi.face;
faceArea = fi.area;
opPlane = fi.plane;
}
}
}
return(foundFace, foundPlane, opFace, opPlane);
}
