- added the set_error_tolerance_factor function to ModBaseT and implemented it in inherited classes as necessary

- added the set_error_tolerance_factor function to BaseDecimaterT, which calls set_error_tolerance_factor for all loaded Mods
- implemented a decimate_constraints_only function for the McDecimater (and adjusted the MixedDecimater accordingly)
- implemented stop criterions for the McDecimater
- added some OpenMP loops for the sample generation to the McDecimater

git-svn-id: http://www.openmesh.org/svnrepo/OpenMesh/trunk@685 fdac6126-5c0c-442c-9429-916003d36597

src/OpenMesh/Tools/Decimater/BaseDecimaterT.cc

@@ -207,6 +207,19 @@ void BaseDecimaterT<Mesh>::preprocess_collapse(CollapseInfo& _ci) {
   cmodule_->preprocess_collapse(_ci);
 }
 
+//-----------------------------------------------------------------------------
+
+template<class Mesh>
+void BaseDecimaterT<Mesh>::set_error_tolerance_factor(double _factor) {
+  if (_factor >= 0.0 && _factor <= 1.0) {
+    typename ModuleList::iterator m_it, m_end = bmodules_.end();
+
+    for (m_it = bmodules_.begin(); m_it != m_end; ++m_it)
+      (*m_it)->set_error_tolerance_factor(_factor);
+
+    cmodule_->set_error_tolerance_factor(_factor);
+  }
+}
 
 //-----------------------------------------------------------------------------
 

src/OpenMesh/Tools/Decimater/BaseDecimaterT.hh

@@ -199,6 +199,16 @@ protected: //---------------------------------------------------- private method
   /// Post-process a collapse
   void postprocess_collapse(CollapseInfo& _ci);
 
+  /**
+   * This provides a function that allows the setting of a percentage
+   * of the original contraint of the modules
+   *
+   * Note that some modules might re-initialize in their
+   * set_error_tolerance_factor function as necessary
+   * @param factor_ has to be in the closed interval between 0.0 and 1.0
+   */
+  void set_error_tolerance_factor(double _factor);
+
 private: //------------------------------------------------------- private data
 
 

src/OpenMesh/Tools/Decimater/DecimaterT.cc

@@ -214,6 +214,7 @@ size_t DecimaterT<Mesh>::decimate(size_t _n_collapses) {
   // delete heap
   heap_.reset();
 
+
   // DON'T do garbage collection here! It's up to the application.
   return n_collapses;
 }
@@ -307,6 +308,7 @@ size_t DecimaterT<Mesh>::decimate_to_faces(size_t _nv, size_t _nf) {
   // delete heap
   heap_.reset();
 
+
   // DON'T do garbage collection here! It's up to the application.
   return n_collapses;
 }

src/OpenMesh/Tools/Decimater/McDecimaterT.cc

@@ -59,6 +59,9 @@
 #else
 #  include <cfloat>
 #endif
+#ifdef USE_OPENMP
+#include <omp.h>
+#endif
 
 //== NAMESPACE ===============================================================
 
@@ -103,17 +106,33 @@ size_t McDecimaterT<Mesh>::decimate(size_t _n_collapses) {
 
   unsigned int n_collapses(0);
 
+  bool collapsesUnchanged = false;
+  // old n_collapses in order to check for convergence
+  unsigned int oldCollapses = 0;
+  // number of iterations where no new collapses where
+  // performed in a row
+  unsigned int noCollapses = 0;
+
   while ( n_collapses <  _n_collapses) {
+    if (noCollapses > 20) {
+      omlog() << "[McDecimater] : no collapses performed in over 20 iterations in a row\n";
+      break;
+    }
 
     // Optimal id and value will be collected during the random sampling
     typename Mesh::HalfedgeHandle bestHandle(-1);
+    typename Mesh::HalfedgeHandle tmpHandle(-1);
     double bestEnergy = FLT_MAX;
+    double energy = FLT_MAX;
 
     // Generate random samples for collapses
+#ifdef USE_OPENMP
+#pragma omp parallel for private(energy,tmpHandle) shared(bestEnergy,bestHandle)
+#endif
     for ( int i = 0; i < (int)randomSamples_; ++i) {
 
       // Random halfedge handle
-      typename Mesh::HalfedgeHandle tmpHandle = typename Mesh::HalfedgeHandle((static_cast<double>(rand()) / RAND_MAX) * (mesh_.n_halfedges()-1) );
+      tmpHandle = typename Mesh::HalfedgeHandle((static_cast<double>(rand()) / RAND_MAX) * (mesh_.n_halfedges()-1) );
 
       // if it is not deleted, we analyse it
       if ( ! mesh_.status(tmpHandle).deleted()  ) {
@@ -122,13 +141,22 @@ size_t McDecimaterT<Mesh>::decimate(size_t _n_collapses) {
 
         // Check if legal we analyze the priority of this collapse operation
         if (this->is_collapse_legal(ci)) {
-          double energy = this->collapse_priority(ci);
+#ifdef USE_OPENMP
+#pragma omp critical(energyUpdate)
+          {
+#endif
+          energy = this->collapse_priority(ci);
 
+          if (energy != ModBaseT<Mesh>::ILLEGAL_COLLAPSE) {
             // Check if the current samples energy is better than any energy before
             if ( energy < bestEnergy ) {
               bestEnergy = energy;
               bestHandle = tmpHandle;
             }
+          }
+#ifdef USE_OPENMP
+          }
+#endif
         } else {
           continue;
         }
@@ -153,6 +181,11 @@ size_t McDecimaterT<Mesh>::decimate(size_t _n_collapses) {
       mesh_.collapse(bestHandle);
       ++n_collapses;
 
+      // store current collapses state
+      oldCollapses = n_collapses;
+      noCollapses = 0;
+      collapsesUnchanged = false;
+
       // update triangle normals
       typename Mesh::VertexFaceIter vf_it = mesh_.vf_iter(ci.v1);
       for (; vf_it; ++vf_it)
@@ -162,6 +195,15 @@ size_t McDecimaterT<Mesh>::decimate(size_t _n_collapses) {
       // post-process collapse
       this->postprocess_collapse(ci);
 
+    } else {
+      if (oldCollapses == n_collapses) {
+        if (collapsesUnchanged == false) {
+          noCollapses = 1;
+          collapsesUnchanged = true;
+        } else {
+          noCollapses++;
+        }
+      }
     }
 
   }
@@ -177,34 +219,43 @@ size_t McDecimaterT<Mesh>::decimate_to_faces(size_t _nv, size_t _nf) {
   if (!this->is_initialized())
     return 0;
 
+  // check if no vertex or face contraints were set
+  if ( (_nv == 0) && (_nf == 1) )
+    return decimate_constraints_only(1.0);
+
   unsigned int nv = mesh_.n_vertices();
   unsigned int nf = mesh_.n_faces();
   unsigned int n_collapses(0);
 
 
-  // check if no vertex or face contraints were set
+  bool collapsesUnchanged = false;
-  bool contraintsOnly = (_nv == 0) && (_nf == 1);
+  // old n_collapses in order to check for convergence
+  unsigned int oldCollapses = 0;
+  // number of iterations where no new collapses where
+  // performed in a row
+  unsigned int noCollapses = 0;
 
-  // check if no legal collapses were found three times in a row
+  while ( (_nv < nv) && (_nf < nf) ) {
-  // for the sampled halfedges
+    if (noCollapses > 20) {
-  bool foundNoLegalCollapsesThrice = false;
+      omlog() << "[McDecimater] : no collapses performed in over 20 iterations in a row\n";
-
+      break;
-  // store the last two amount of legal collapses found
+    }
-  int lastLegalCollapses = -1;
-  int beforeLastLegalCollapses = -1;
-
-  while ( !foundNoLegalCollapsesThrice && (_nv < nv) && (_nf < nf) ) {
 
     // Optimal id and value will be collected during the random sampling
     typename Mesh::HalfedgeHandle bestHandle(-1);
+    typename Mesh::HalfedgeHandle tmpHandle(-1);
     double bestEnergy = FLT_MAX;
+    double energy = FLT_MAX;
+
 
     // Generate random samples for collapses
-    unsigned int legalCollapses = 0;
+#ifdef USE_OPENMP
+#pragma omp parallel for private(energy,tmpHandle) shared(bestEnergy,bestHandle)
+#endif
     for ( int i = 0; i < (int)randomSamples_; ++i) {
 
       // Random halfedge handle
-      typename Mesh::HalfedgeHandle tmpHandle = typename Mesh::HalfedgeHandle((static_cast<double>(rand()) / RAND_MAX) * (mesh_.n_halfedges()-1) );
+      tmpHandle = typename Mesh::HalfedgeHandle((static_cast<double>(rand()) / RAND_MAX) * (mesh_.n_halfedges()-1) );
 
       // if it is not deleted, we analyse it
       if ( ! mesh_.status(tmpHandle).deleted()  ) {
@@ -213,14 +264,22 @@ size_t McDecimaterT<Mesh>::decimate_to_faces(size_t _nv, size_t _nf) {
 
         // Check if legal we analyze the priority of this collapse operation
         if (this->is_collapse_legal(ci)) {
-          ++legalCollapses;
+#ifdef USE_OPENMP
-          double energy = this->collapse_priority(ci);
+#pragma omp critical(energyUpdate)
+          {
+#endif
+          energy = this->collapse_priority(ci);
 
+          if (energy != ModBaseT<Mesh>::ILLEGAL_COLLAPSE) {
             // Check if the current samples energy is better than any energy before
             if ( energy < bestEnergy ) {
               bestEnergy = energy;
               bestHandle = tmpHandle;
             }
+            }
+#ifdef USE_OPENMP
+          }
+#endif
         } else {
           continue;
         }
@@ -228,15 +287,6 @@ size_t McDecimaterT<Mesh>::decimate_to_faces(size_t _nv, size_t _nf) {
 
     }
 
-    if (contraintsOnly) {
-      // check if no legal collapses were found three times in a row
-      foundNoLegalCollapsesThrice = (beforeLastLegalCollapses == 0) && (lastLegalCollapses == 0) && (legalCollapses == 0);
-
-      // store amount of last legal collapses found
-      beforeLastLegalCollapses = lastLegalCollapses;
-      lastLegalCollapses = legalCollapses;
-    }
-
     // Found the best energy?
     if ( bestEnergy != FLT_MAX ) {
 
@@ -267,6 +317,11 @@ size_t McDecimaterT<Mesh>::decimate_to_faces(size_t _nv, size_t _nf) {
       mesh_.collapse(bestHandle);
       ++n_collapses;
 
+      // store current collapses state
+      oldCollapses = n_collapses;
+      noCollapses = 0;
+      collapsesUnchanged = false;
+
       // update triangle normals
       typename Mesh::VertexFaceIter vf_it = mesh_.vf_iter(ci.v1);
       for (; vf_it; ++vf_it)
@@ -276,6 +331,15 @@ size_t McDecimaterT<Mesh>::decimate_to_faces(size_t _nv, size_t _nf) {
       // post-process collapse
       this->postprocess_collapse(ci);
 
+    } else {
+      if (oldCollapses == n_collapses) {
+        if (collapsesUnchanged == false) {
+          noCollapses = 1;
+          collapsesUnchanged = true;
+        } else {
+          noCollapses++;
+        }
+      }
     }
 
   }
@@ -284,6 +348,155 @@ size_t McDecimaterT<Mesh>::decimate_to_faces(size_t _nv, size_t _nf) {
   return n_collapses;
 }
 
+//-----------------------------------------------------------------------------
+
+template<class Mesh>
+size_t McDecimaterT<Mesh>::decimate_constraints_only(float _factor) {
+  if (!this->is_initialized())
+    return 0;
+
+  if (_factor < 1.0)
+    this->set_error_tolerance_factor(_factor);
+
+  unsigned int n_collapses(0);
+  unsigned int nv = mesh_.n_vertices();
+  unsigned int nf = mesh_.n_faces();
+
+  bool lastCollapseIllegal = false;
+  // number of illegal collapses that occured in a row
+  unsigned int illegalCollapses = 0;
+
+  bool collapsesUnchanged = false;
+  // old n_collapses in order to check for convergence
+  unsigned int oldCollapses = 0;
+  // number of iterations where no new collapses where
+  // performed in a row
+  unsigned int noCollapses = 0;
+
+
+  while ( (noCollapses <= 20) && (illegalCollapses <= 10) && (nv > 0) && (nf > 1) ) {
+
+    // Optimal id and value will be collected during the random sampling
+    typename Mesh::HalfedgeHandle bestHandle(-1);
+    typename Mesh::HalfedgeHandle tmpHandle(-1);
+    double bestEnergy = FLT_MAX;
+    double energy = FLT_MAX;
+
+    // Generate random samples for collapses
+#ifdef USE_OPENMP
+#pragma omp parallel for private(energy,tmpHandle) shared(bestEnergy,bestHandle)
+#endif
+    for ( int i = 0; i < (int)randomSamples_; ++i) {
+
+      // Random halfedge handle
+      tmpHandle = typename Mesh::HalfedgeHandle((static_cast<double>(rand()) / RAND_MAX) * (mesh_.n_halfedges()-1) );
+
+      // if it is not deleted, we analyse it
+      if ( ! mesh_.status(tmpHandle).deleted()  ) {
+
+        CollapseInfo ci(mesh_, tmpHandle);
+
+        // Check if legal we analyze the priority of this collapse operation
+        if (this->is_collapse_legal(ci)) {
+#ifdef USE_OPENMP
+#pragma omp critical(energyUpdate)
+          {
+#endif
+
+          energy = this->collapse_priority(ci);
+
+          if (energy == ModBaseT<Mesh>::ILLEGAL_COLLAPSE){
+            if (lastCollapseIllegal) {
+              illegalCollapses++;
+            } else {
+              illegalCollapses = 1;
+              lastCollapseIllegal = true;
+            }
+          } else {
+            illegalCollapses = 0;
+            lastCollapseIllegal = false;
+
+            // Check if the current samples energy is better than any energy before
+            if ( energy < bestEnergy ) {
+              bestEnergy = energy;
+              bestHandle = tmpHandle;
+            }
+          }
+#ifdef USE_OPENMP
+          }
+#endif
+        } else {
+          continue;
+        }
+      }
+
+    }
+
+    // Found the best energy?
+    if ( bestEnergy != FLT_MAX ) {
+
+      // setup collapse info
+      CollapseInfo ci(mesh_, bestHandle);
+
+      // check topological correctness AGAIN !
+      if (!this->is_collapse_legal(ci))
+        continue;
+
+      // adjust complexity in advance (need boundary status)
+
+      // One vertex is killed by the collapse
+      --nv;
+
+      // If we are at a boundary, one face is lost,
+      // otherwise two
+      if (mesh_.is_boundary(ci.v0v1) || mesh_.is_boundary(ci.v1v0))
+        --nf;
+      else
+        nf -= 2;
+
+      // pre-processing
+      this->preprocess_collapse(ci);
+
+      // perform collapse
+      mesh_.collapse(bestHandle);
+      ++n_collapses;
+
+      // store current collapses state
+      oldCollapses = n_collapses;
+      noCollapses = 0;
+      collapsesUnchanged = false;
+
+
+      // update triangle normals
+      typename Mesh::VertexFaceIter vf_it = mesh_.vf_iter(ci.v1);
+      for (; vf_it; ++vf_it)
+        if (!mesh_.status(vf_it).deleted())
+          mesh_.set_normal(vf_it, mesh_.calc_face_normal(vf_it.handle()));
+
+      // post-process collapse
+      this->postprocess_collapse(ci);
+
+    } else {
+      if (oldCollapses == n_collapses) {
+        if (collapsesUnchanged == false) {
+          noCollapses = 1;
+          collapsesUnchanged = true;
+        } else {
+          noCollapses++;
+        }
+      }
+    }
+
+  }
+
+  if (_factor < 1.0)
+    this->set_error_tolerance_factor(1.0);
+
+  // DON'T do garbage collection here! It's up to the application.
+  return n_collapses;
+
+}
+
 //=============================================================================
 }// END_NS_MC_DECIMATER
 } // END_NS_OPENMESH

src/OpenMesh/Tools/Decimater/McDecimaterT.hh

@@ -111,6 +111,12 @@ public:
    */
   size_t decimate_to_faces( size_t  _n_vertices=0, size_t _n_faces=0 );
 
+  /**
+   * Decimate only with constraints, while _factor gives the
+   * percentage of the constraints that should be used
+   */
+  size_t decimate_constraints_only(float _factor);
+
   size_t samples(){return randomSamples_;}
   void set_samples(const size_t _value){randomSamples_ = _value;}
 

src/OpenMesh/Tools/Decimater/MixedDecimaterT.cc

@@ -94,6 +94,7 @@ size_t MixedDecimaterT<Mesh>::decimate(const size_t _n_collapses, const float _m
     r_collapses = McDecimaterT<Mesh>::decimate(n_collapses_mc);
   if (_mc_factor < 1.0)
     r_collapses += DecimaterT<Mesh>::decimate(n_collapses_inc);
+
   return r_collapses;
 
 }
@@ -106,6 +107,8 @@ size_t MixedDecimaterT<Mesh>::decimate_to_faces(const size_t  _n_vertices,const
   std::size_t r_collapses = 0;
   if (_mc_factor > 0.0)
   {
+    bool constraintsOnly = (_n_vertices == 0) && (_n_faces == 1);
+    if (!constraintsOnly) {
       size_t mesh_faces = this->mesh().n_faces();
       size_t mesh_vertices = this->mesh().n_vertices();
       //reduce the mesh only for _mc_factor
@@ -113,6 +116,9 @@ size_t MixedDecimaterT<Mesh>::decimate_to_faces(const size_t  _n_vertices,const
       size_t n_faces_mc = static_cast<size_t>(mesh_faces - _mc_factor * (mesh_faces - _n_faces));
 
       r_collapses = McDecimaterT<Mesh>::decimate_to_faces(n_vertices_mc, n_faces_mc);
+    } else {
+      r_collapses = McDecimaterT<Mesh>::decimate_constraints_only(_mc_factor);
+    }
   }
 
   //update the mesh::n_vertices function, otherwise the next Decimater function will delete to much
@@ -122,6 +128,7 @@ size_t MixedDecimaterT<Mesh>::decimate_to_faces(const size_t  _n_vertices,const
   if (_mc_factor < 1.0)
     r_collapses += DecimaterT<Mesh>::decimate_to_faces(_n_vertices,_n_faces);
 
+
   return r_collapses;
 }
 

src/OpenMesh/Tools/Decimater/ModAspectRatioT.cc

@@ -173,6 +173,20 @@ float ModAspectRatioT<MeshT>::collapse_priority(const CollapseInfo& _ci) {
   }
 }
 
+//-----------------------------------------------------------------------------
+
+template<class MeshT>
+void ModAspectRatioT<MeshT>::set_error_tolerance_factor(double _factor) {
+  if (_factor >= 0.0 && _factor <= 1.0) {
+    // the smaller the factor, the larger min_aspect_ gets
+    // thus creating a stricter constraint
+    // division by (2.0 - error_tolerance_factor_) is for normalization
+    double min_aspect = min_aspect_ * (2.0 - _factor) / (2.0 - this->error_tolerance_factor_);
+    set_aspect_ratio(1.0/min_aspect);
+    this->error_tolerance_factor_ = _factor;
+  }
+}
+
 //=============================================================================
 }
 }

src/OpenMesh/Tools/Decimater/ModAspectRatioT.hh

@@ -118,6 +118,9 @@ class ModAspectRatioT: public ModBaseT<MeshT> {
     /// update aspect ratio of one-ring
     void preprocess_collapse(const CollapseInfo& _ci);
 
+    /// set percentage of aspect ratio
+    void set_error_tolerance_factor(double _factor);
+
   private:
 
     /** \brief return aspect ratio (length/height) of triangle

src/OpenMesh/Tools/Decimater/ModBaseT.hh

@@ -203,7 +203,7 @@ protected:
   /// Default constructor
   /// \see \ref decimater_docu
   ModBaseT(MeshT& _mesh, bool _is_binary)
-    : mesh_(_mesh), is_binary_(_is_binary) {}
+    : error_tolerance_factor_(1.0), mesh_(_mesh), is_binary_(_is_binary) {}
 
 public:
 
@@ -255,6 +255,18 @@ public: // common interface
    virtual void postprocess_collapse(const CollapseInfoT<MeshT>& /* _ci */)
    {}
 
+   /**
+    * This provides a function that allows the setting of a percentage
+    * of the original contraint.
+    *
+    * Note that the module might need to be re-initialized again after
+    * setting the percentage
+    * @param factor_ has to be in the closed interval between 0.0 and 1.0
+    */
+   virtual void set_error_tolerance_factor(double _factor) {
+     if (_factor >= 0.0 && _factor <= 1.0)
+       error_tolerance_factor_ = _factor;
+   }
 
 
 protected:
@@ -262,6 +274,9 @@ protected:
   /// Access the mesh associated with the decimater.
   MeshT& mesh() { return mesh_; }
 
+  // current percentage of the original constraint
+  double error_tolerance_factor_;
+
 private:
 
   // hide copy constructor & assignemnt

src/OpenMesh/Tools/Decimater/ModEdgeLengthT.cc

@@ -76,6 +76,20 @@ float ModEdgeLengthT<MeshT>::collapse_priority(const CollapseInfo& _ci) {
   return ( (sqr_length <= sqr_edge_length_) ? sqr_length : float(Base::ILLEGAL_COLLAPSE));
 }
 
+//-----------------------------------------------------------------------------
+
+template<class MeshT>
+void ModEdgeLengthT<MeshT>::set_error_tolerance_factor(double _factor) {
+  if (_factor >= 0.0 && _factor <= 1.0) {
+    // the smaller the factor, the smaller edge_length_ gets
+    // thus creating a stricter constraint
+    // division by error_tolerance_factor_ is for normalization
+    float edge_length = edge_length_ * _factor / this->error_tolerance_factor_;
+    set_edge_length(edge_length);
+    this->error_tolerance_factor_ = _factor;
+  }
+}
+
 //=============================================================================
 }
 }

src/OpenMesh/Tools/Decimater/ModEdgeLengthT.hh

@@ -99,6 +99,9 @@ class ModEdgeLengthT: public ModBaseT<MeshT> {
      */
     float collapse_priority(const CollapseInfo& _ci);
 
+    /// set the percentage of edge length
+    void set_error_tolerance_factor(double _factor);
+
   private:
 
     Mesh& mesh_;

src/OpenMesh/Tools/Decimater/ModHausdorffT.cc

@@ -269,9 +269,21 @@ collapse_priority(const CollapseInfo& _ci)
   return ( ok ? Base::LEGAL_COLLAPSE : Base::ILLEGAL_COLLAPSE );
 }
 
-
 //-----------------------------------------------------------------------------
 
+template<class MeshT>
+void ModHausdorffT<MeshT>::set_error_tolerance_factor(double _factor) {
+  if (_factor >= 0.0 && _factor <= 1.0) {
+    // the smaller the factor, the smaller tolerance gets
+    // thus creating a stricter constraint
+    // division by error_tolerance_factor_ is for normalization
+    Scalar tolerance = tolerance_ * _factor / this->error_tolerance_factor_;
+    set_tolerance(tolerance);
+    this->error_tolerance_factor_ = _factor;
+  }
+}
+
+//-----------------------------------------------------------------------------
 
 template <class MeshT>
 void
@@ -380,9 +392,12 @@ compute_sqr_error(FaceHandle _fh, const Point& _p) const
 #pragma omp parallel for private(e) shared(emax)
   for (int i = 0; i < pointsCount; ++i) {
     e =  distPointTriangleSquared(points[i], p0, p1, p2, dummy);
+#pragma omp critical(emaxUpdate)
+    {
     if (e > emax)
       emax = e;
     }
+  }
 #else
   for (; p_it!=p_end; ++p_it) {
     e =  distPointTriangleSquared(*p_it, p0, p1, p2, dummy);

src/OpenMesh/Tools/Decimater/ModHausdorffT.hh

@@ -124,6 +124,9 @@ class ModHausdorffT: public ModBaseT<MeshT> {
     /// re-distribute points
     virtual void postprocess_collapse(const CollapseInfo& _ci);
 
+    /// set the percentage of tolerance
+    void set_error_tolerance_factor(double _factor);
+
   private:
 
     /// squared distance from point _p to triangle (_v0, _v1, _v2)

src/OpenMesh/Tools/Decimater/ModNormalDeviationT.hh

@@ -191,6 +191,18 @@ public:
     return (max_angle < 0.5 * normal_deviation_ ? max_angle : float( Base::ILLEGAL_COLLAPSE ));
   }
 
+  /// set the percentage of normal deviation
+  void set_error_tolerance_factor(double _factor) {
+    if (_factor >= 0.0 && _factor <= 1.0) {
+      // the smaller the factor, the smaller normal_deviation_ gets
+      // thus creating a stricter constraint
+      // division by error_tolerance_factor_ is for normalization
+      Scalar normal_deviation = (normal_deviation_ * 180.0/M_PI) * _factor / this->error_tolerance_factor_;
+      set_normal_deviation(normal_deviation);
+      this->error_tolerance_factor_ = _factor;
+    }
+  }
+
 
   void  postprocess_collapse(const CollapseInfo& _ci) {
     // account for changed normals

src/OpenMesh/Tools/Decimater/ModNormalFlippingT.hh

@@ -141,6 +141,17 @@ public:
     return float( (c < min_cos_) ? Base::ILLEGAL_COLLAPSE : Base::LEGAL_COLLAPSE );
   }
 
+  /// set the percentage of maximum normal deviation
+  void set_error_tolerance_factor(double _factor) {
+    if (_factor >= 0.0 && _factor <= 1.0) {
+      // the smaller the factor, the smaller max_deviation_ gets
+      // thus creating a stricter constraint
+      // division by error_tolerance_factor_ is for normalization
+      float max_normal_deviation = (max_deviation_ * 180.0/M_PI) * _factor / this->error_tolerance_factor_;
+      set_max_normal_deviation(max_normal_deviation);
+      this->error_tolerance_factor_ = _factor;
+    }
+  }
 
 
 public:

src/OpenMesh/Tools/Decimater/ModQuadricT.cc

@@ -129,6 +129,23 @@ initialize()
   }
 }
 
+//-----------------------------------------------------------------------------
+
+template<class MeshT>
+void ModQuadricT<MeshT>::set_error_tolerance_factor(double _factor) {
+  if (this->is_binary()) {
+    if (_factor >= 0.0 && _factor <= 1.0) {
+      // the smaller the factor, the smaller max_err_ gets
+      // thus creating a stricter constraint
+      // division by error_tolerance_factor_ is for normalization
+      double max_err = max_err_ * _factor / this->error_tolerance_factor_;
+      set_max_err(max_err);
+      this->error_tolerance_factor_ = _factor;
+
+      initialize();
+    }
+  }
+}
 
 //=============================================================================
 } // END_NS_DECIMATER

src/OpenMesh/Tools/Decimater/ModQuadricT.hh

@@ -138,6 +138,9 @@ public: // inherited
       Base::mesh().property(quadrics_, _ci.v0);
   }
 
+  /// set the percentage of maximum quadric error
+  void set_error_tolerance_factor(double _factor);
+
 
 
 public: // specific methods

src/OpenMesh/Tools/Decimater/ModRoundnessT.hh

@@ -171,6 +171,19 @@ class ModRoundnessT : public ModBaseT<MeshT>
     return (float) priority;
   }
 
+  /// set the percentage of minimum roundness
+  void set_error_tolerance_factor(double _factor) {
+    if (this->is_binary()) {
+      if (_factor >= 0.0 && _factor <= 1.0) {
+        // the smaller the factor, the smaller min_r_ gets
+        // thus creating a stricter constraint
+        // division by error_tolerance_factor_ is for normalization
+        value_type min_roundness = min_r_ * _factor / this->error_tolerance_factor_;
+        set_min_roundness(min_roundness);
+        this->error_tolerance_factor_ = _factor;
+      }
+}
+  }
 
 
 public: // specific methods