MeshFlattening: initial commit

2017-09-07 18:39:13 +02:00
parent 7a623ca1c2
commit 77bebe7a02
8 changed files with 1533 additions and 0 deletions
--- a/src/Mod/MeshPart/App/MeshFlattening.cpp
+++ b/src/Mod/MeshPart/App/MeshFlattening.cpp
@@ -0,0 +1,142 @@
+/***************************************************************************
+ *   Copyright (c) 2017 Lorenz Lechner                                     *
+ *                                                                         *
+ *   This file is part of the FreeCAD CAx development system.              *
+ *                                                                         *
+ *   This library is free software; you can redistribute it and/or         *
+ *   modify it under the terms of the GNU Library General Public           *
+ *   License as published by the Free Software Foundation; either          *
+ *   version 2 of the License, or (at your option) any later version.      *
+ *                                                                         *
+ *   This library  is distributed in the hope that it will be useful,      *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU Library General Public License for more details.                  *
+ *                                                                         *
+ *   You should have received a copy of the GNU Library General Public     *
+ *   License along with this library; see the file COPYING.LIB. If not,    *
+ *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
+ *   Suite 330, Boston, MA  02111-1307, USA                                *
+ *                                                                         *
+ ***************************************************************************/
+
+
+#include "MeshFlattening.h"
+#include "MeshFlatteningLscmRelax.h"
+#include <Poly_Triangulation.hxx>
+#include <BRep_Tool.hxx>
+#include <Geom_Surface.hxx>
+#include <Geom_BSplineSurface.hxx>
+
+FaceUnwrapper::FaceUnwrapper(const TopoDS_Face& face)
+{
+    int i = 0;
+//  transform to nurbs:
+    TopLoc_Location location;
+    
+//  triangulate:
+    const Handle(Poly_Triangulation) &triangulation = BRep_Tool::Triangulation(face, location);
+
+    if (triangulation.IsNull())
+        throw std::runtime_error("null triangulation in face construction");
+
+//  compute uv coordinates
+    if (triangulation->HasUVNodes())
+    {
+        const TColgp_Array1OfPnt2d &_uv_nodes = triangulation->UVNodes();
+        this->uv_nodes.resize(triangulation->NbNodes(), 2);
+        i = 0;
+        for (gp_Pnt2d _uv_node: _uv_nodes)
+        {
+            this->uv_nodes.row(i) << _uv_node.X(), _uv_node.Y();
+            i++;
+        }
+    }
+// 
+    const TColgp_Array1OfPnt &_nodes = triangulation->Nodes();
+    this->xyz_nodes.resize(triangulation->NbNodes(), 3);
+    i = 0;
+    for (gp_Pnt _node: _nodes)
+    {
+        this->xyz_nodes.row(i) << _node.X(), _node.Y(), _node.Z();
+        i++;
+    }
+    
+    const Poly_Array1OfTriangle &_tris = triangulation->Triangles();
+    this->tris.resize(triangulation->NbTriangles(), 3);
+    i = 0;
+    for (Poly_Triangle _tri: _tris)
+    {
+        int n1, n2, n3;
+        _tri.Get(n1, n2, n3);
+        this->tris.row(i) << n1-1, n2-1, n3-1;
+        i++;
+    }
+}
+
+void FaceUnwrapper::findFlatNodes()
+{
+    std::vector<long> fixed_pins;
+    LscmRelax mesh_flattener(this->xyz_nodes.transpose(), this->tris.transpose(), fixed_pins);
+    mesh_flattener.lscm();
+    mesh_flattener.relax(0.9);
+    this->ze_nodes = mesh_flattener.flat_vertices.transpose();
+}
+
+ColMat<double, 3> FaceUnwrapper::interpolateNurbsFace(const TopoDS_Face& face)
+{
+    // extract xyz poles, knots, weights, degree
+    const Handle(Geom_Surface) &_surface = BRep_Tool::Surface(face);
+    const Handle(Geom_BSplineSurface) &_bspline = Handle(Geom_BSplineSurface)::DownCast(_surface);
+    const TColStd_Array1OfReal &_uknots = _bspline->UKnotSequence();
+    const TColStd_Array1OfReal &_vknots = _bspline->VKnotSequence();    
+    
+    Eigen::VectorXd weights;
+    weights.resize(_bspline->NbUPoles() * _bspline->NbVPoles());
+    int i = 0;
+    for (int u=1; u <= _bspline->NbUPoles(); u++)
+    {
+        for (int v=1; v <= _bspline->NbVPoles(); v++)
+        {
+            weights[i] = _bspline->Weight(u, v);
+            i++;
+        }
+    }
+    
+    Eigen::VectorXd u_knots;
+    Eigen::VectorXd v_knots;
+    u_knots.resize(_uknots.Size());
+    v_knots.resize(_vknots.Size());
+    for (int u=1; u <= _uknots.Size(); u++)
+    {
+        u_knots[u - 1] = _uknots.Value(u);
+    }
+    for (int v=1; v <= _vknots.Size(); v++)
+    {
+        v_knots[v - 1] = _vknots.Value(v);
+    }
+    
+
+    nu = nurbs::NurbsBase2D(u_knots, v_knots, weights, _bspline->UDegree(), _bspline->VDegree());
+    A = nu.getInfluenceMatrix(this->uv_nodes);
+    
+    Eigen::LeastSquaresConjugateGradient<spMat > solver;
+    solver.compute(A);
+    ColMat<double, 2> ze_poles;
+    ColMat<double, 3> flat_poles;
+    ze_poles.resize(weights.rows(), 2);
+    flat_poles.resize(weights.rows(), 3);
+    flat_poles.setZero();
+    ze_poles = solver.solve(ze_nodes);
+    flat_poles.col(0) << ze_poles.col(0);
+    flat_poles.col(1) << ze_poles.col(1);
+    return flat_poles;    
+}
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