diff --git a/apps/nexus/nexusmt.cpp b/apps/nexus/nexusmt.cpp
index 5e78c3eb..7bb607d9 100644
--- a/apps/nexus/nexusmt.cpp
+++ b/apps/nexus/nexusmt.cpp
@@ -26,23 +26,36 @@ bool FrustumPolicy::Expand(unsigned int patch, Nexus::PatchInfo &entry) {
   return entry.error > error * frustum.Resolution(dist);
 } */
 
-float FrustumMetric::GetError(Node *node) {
+float Metric::GetError(Node *node) {
   float max_error = 0;
-  std::vector<Frag>::iterator frag;
-  for(frag = node->frags.begin(); frag != node->frags.end(); frag++) {                
-    vector<unsigned int>::iterator cell;
-    for(cell = (*frag).begin(); cell != (*frag).end(); cell++) {              
-      Nexus::PatchInfo &entry = (*index)[*cell];    
-      Sphere3f &sphere = entry.sphere;
-      float dist = Distance(sphere, frustum.ViewPoint());
-      if(dist < 0) break;
-      float error = entry.error/frustum.Resolution(dist);
-      if(frustum.IsOutside(sphere.Center(), sphere.Radius()))
-        error *= 4;
-      if(max_error < error) max_error = error;
-    }	   
+  vector<Frag>::iterator frag;
+  for(frag = node->frags.begin(); frag != node->frags.end(); frag++) {
+    float error = GetError(*frag);
+    if(max_error < error) max_error = error;
   }
-  return max_error; 
+  return max_error;
+}
+
+float Metric::GetError(Frag &frag) {
+  float max_error = 0;
+  vector<unsigned int>::iterator cell;
+  for(cell = frag.begin(); cell != frag.end(); cell++) {              
+    float error = GetError(*cell);
+    if(max_error < error) max_error = error;
+  }
+  return max_error;
+}
+
+float FrustumMetric::GetError(unsigned int cell) {
+  float max_error = 0;
+  Nexus::PatchInfo &entry = (*index)[cell];    
+  Sphere3f &sphere = entry.sphere;
+  float dist = Distance(sphere, frustum.ViewPoint());
+  if(dist < 0) return 1e40;
+  float error = entry.error/frustum.Resolution(dist);
+  if(frustum.IsOutside(sphere.Center(), sphere.Radius()))
+    error /= 4;
+  return error;
 }
 
 void Policy::Init() {
@@ -472,24 +485,21 @@ void NexusMt::Select(vector<unsigned int> &selected) {
   }
 }
 
-void NexusMt::PushNode(Node *node, vector<TNode> &heap) {
-  if(node->pushed) return; 
-
-  float error = metric->GetError(node);
-  heap.push_back(TNode(node, error));
-  push_heap(heap.begin(), heap.end());    
-}
-
 void NexusMt::VisitNode(Node *node, vector<TNode> &heap) {
   if(node->visited) return;
   
   vector<Node *>::iterator i;
   for(i = node->in.begin(); i != node->in.end(); i++)     
-      VisitNode(*i, heap);
+    VisitNode(*i, heap);
+  
+  for(unsigned int k = 0; k < node->out.size(); k++) {
+    Node *outnode = node->out[k];
+    float error = metric->GetError(node->frags[k]);
+    //  if(node->pushed) continue
+    heap.push_back(TNode(outnode, error));
+    push_heap(heap.begin(), heap.end());    
+  }
   
-  for(i = node->out.begin(); i != node->out.end(); i++)
-    PushNode(*i, heap);  
-
   node->visited = true;
   policy.NodeVisited(node);
 }
diff --git a/apps/nexus/nexusmt.h b/apps/nexus/nexusmt.h
index 21b5a09f..86b2a715 100644
--- a/apps/nexus/nexusmt.h
+++ b/apps/nexus/nexusmt.h
@@ -33,21 +33,23 @@ namespace nxs {
  public:
    vector<Nexus::PatchInfo> *index;
 
-   virtual float GetError(Node *node) = 0;   
+   float GetError(Node *node);   
+   float GetError(Frag &frag);
+   virtual float GetError(unsigned int cell) = 0;
    virtual void GetView() {}   
  };
 
  class FlatMetric: public Metric {
  public:
    void GetView() {}
-   float GetError(Node *node);   
+   float GetError(unsigned int cell);   
  };
 
  class DeltaMetric: public Metric {
  public:
    vcg::Point3f delta;
    void GetView() {}
-   float GetError(Node *node);   
+   float GetError(unsigned int cell);   
  };
 
  class FrustumMetric: public Metric {
@@ -55,7 +57,7 @@ namespace nxs {
    vcg::Frustumf frustum;      
 
    void GetView() { frustum.GetView(); }
-   float GetError(Node *node);   
+   float GetError(unsigned int cell);   
  };
 
  class Policy {
@@ -139,7 +141,6 @@ class NexusMt: public Nexus {
  protected:
   void LoadHistory();
   void ClearHistory();
-  void PushNode(Node *node, std::vector<TNode> &heap);
   void VisitNode(Node *node, std::vector<TNode> &heap);
   void Select(std::vector<unsigned int> &selected);
   Patch &LoadPatch(unsigned int p);
diff --git a/apps/nexus/nxsbuild.cpp b/apps/nexus/nxsbuild.cpp
index db2f1e66..3f803c0e 100644
--- a/apps/nexus/nxsbuild.cpp
+++ b/apps/nexus/nxsbuild.cpp
@@ -85,7 +85,10 @@ void nxs::NexusFill(Crude &crude,
 		    VertRemap &vert_remap,
 		    VFile<RemapLink> &border_remap) {
   
-  
+
+  //TODO: is it faster to collect faces and vertices
+  //from all around or better to pass linearly all the dataset
+  //and write where needed? i wonder.
   //finally for every patch we collect the vertices
   //and fill the patch.
   //we need to remember start and size in border_remap;
@@ -93,8 +96,6 @@ void nxs::NexusFill(Crude &crude,
   for(unsigned int i = 0; i < nexus.index.size(); i++) {
     Patch patch = nexus.GetPatch(i);
     Nexus::PatchInfo &entry = nexus.index[i];
-    //    cerr << "entryf: " << entry.nface << endl;
-    //    cerr << "nf: " << patch.nf << endl;
     
     //make a copy of faces (we need to write there :P)
     Crude::Face *faces = new Crude::Face[patch.nf];
@@ -113,11 +114,11 @@ void nxs::NexusFill(Crude &crude,
       for(int j = 0; j < 3; j++) {
         if(!remap.count(face[j])) {          
 	  Point3f &v = crude.vert[face[j]];
-          patch.VertBegin()[remap.size()] = v;
+          patch.Vert(remap.size()) = v;
 	  entry.sphere.Add(v);
           remap[face[j]] = count++;
         }
-	patch.FaceBegin()[k*3 + j] = remap[face[j]];
+	patch.Face(k)[j] = remap[face[j]];
       }
     }
     assert(count == remap.size());
@@ -156,7 +157,7 @@ void nxs::NexusFill(Crude &crude,
 
   //and last convert RemapLinks into Links
 
-
+  //TODO probably this part is really slow
   for(unsigned int i = 0; i < nexus.borders.borders.size(); i++) {
     BorderEntry &local = nexus.borders.borders[i];
     //* 2 is to accomodate future borders