remove colinear points

* this fix the issue that colinear points aren't anymore after the offset2 from slice_closing_radius.
 * this allow the XY hole compensation to apply correctly
 * up the max concave angle accepted to detect hole to grow by XY compensation from 0.06° to 6°.

src/libslic3r/Polygon.cpp

@@ -316,6 +316,35 @@ Point Polygon::point_projection(const Point &point) const
     return proj;
 }
 
+size_t Polygon::remove_colinear_points(coord_t max_offset){
+    size_t nb_del = 0;
+    if (points.size() < 3) return 0;
+
+    coord_t min_dist = max_offset * max_offset;
+    while (points.size() > 2 && Line::distance_to_squared(points[0], points.back(), points[1]) < min_dist){
+        //colinear! delete!
+        points.erase(points.begin());
+        nb_del++;
+    }
+    for (size_t idx = 1; idx < points.size()-1; ) {
+        //if (Line(previous, points[idx + 1]).distance_to(points[idx]) < SCALED_EPSILON){
+        if (Line::distance_to_squared(points[idx], points[idx-1], points[idx + 1]) < min_dist){
+            //colinear! delete!
+            points.erase(points.begin() + idx);
+            nb_del++;
+        } else {
+            idx++;
+        }
+    }
+    while (points.size() > 2 && Line::distance_to_squared(points.back(), points[points.size()-2], points.front()) < min_dist) {
+        //colinear! delete!
+        points.erase(points.end()-1);
+        nb_del++;
+    }
+
+    return nb_del;
+}
+
 BoundingBox get_extents(const Polygon &poly) 
 { 
     return poly.bounding_box();

src/libslic3r/Polygon.hpp

@@ -59,6 +59,9 @@ public:
     Points convex_points(double angle = PI) const;
     // Projection of a point onto the polygon.
     Point point_projection(const Point &point) const;
+    /// remove points that are (almost) on an existing line from previous & next point.
+    /// return number of point removed
+    size_t remove_colinear_points(coord_t max_offset);
 };
 
 extern BoundingBox get_extents(const Polygon &poly);

src/libslic3r/PrintConfig.cpp

@@ -1870,10 +1870,10 @@ void PrintConfigDef::init_fff_params()
     def = this->add("resolution", coFloat);
     def->label = L("Resolution");
     def->tooltip = L("Minimum detail resolution, used to simplify the input file for speeding up "
-                   "the slicing job and reducing memory usage. High-resolution models often carry "
+        "the slicing job and reducing memory usage. High-resolution models often carry "
-                   "more detail than printers can render. Set to zero to disable any simplification "
+        "more detail than printers can render. Set to zero to disable any simplification "
-                   "and use full resolution from input. "
+        "and use full resolution from input. "
-                   "\nNote: slic3r simplify the geometry with a treshold of 0.0125mm and has an internal resolution of 0.0001mm.");
+        "\nNote: slic3r simplify the geometry with a treshold of 0.0125mm and has an internal resolution of 0.0001mm.");
     def->sidetext = L("mm");
     def->cli = "resolution=f";
     def->min = 0;
@@ -2254,6 +2254,20 @@ void PrintConfigDef::init_fff_params()
     def->mode = comExpert;
     def->default_value = new ConfigOptionStrings { "; Filament gcode\n" };
 
+
+    def = this->add("model_precision", coFloat);
+    def->label = L("Model rounding precision");
+    def->full_label = L("Model rounding precision");
+    def->category = L("Advanced");
+    def->tooltip = L("This is the rounding error of the input object."
+        " It's used to align points that should be in the same line."
+        " Put 0 to disable.");
+    def->sidetext = L("mm");
+    def->cli = "model-precision=f";
+    def->min = 0;
+    def->mode = comExpert;
+    def->default_value = new ConfigOptionFloat(0.0001);
+
     def = this->add("single_extruder_multi_material", coBool);
     def->label = L("Single Extruder Multi Material");
     def->tooltip = L("The printer multiplexes filaments into a single hot end.");

src/libslic3r/PrintConfig.hpp

@@ -453,13 +453,14 @@ public:
     ConfigOptionBool                clip_multipart_objects;
     ConfigOptionBool                dont_support_bridges;
     ConfigOptionFloat               elefant_foot_compensation;
+    ConfigOptionBool                exact_last_layer_height;
     ConfigOptionFloatOrPercent      extrusion_width;
     ConfigOptionFloatOrPercent      first_layer_height;
     ConfigOptionBool                infill_only_where_needed;
     // Force the generation of solid shells between adjacent materials/volumes.
     ConfigOptionBool                interface_shells;
     ConfigOptionFloat               layer_height;
-    ConfigOptionBool                exact_last_layer_height;
+    ConfigOptionFloat               model_precision;
     ConfigOptionInt                 raft_layers;
     ConfigOptionEnum<SeamPosition>  seam_position;
     ConfigOptionBool                seam_travel;
@@ -505,12 +506,13 @@ protected:
         OPT_PTR(clip_multipart_objects);
         OPT_PTR(dont_support_bridges);
         OPT_PTR(elefant_foot_compensation);
+        OPT_PTR(exact_last_layer_height);
         OPT_PTR(extrusion_width);
         OPT_PTR(first_layer_height);
         OPT_PTR(infill_only_where_needed);
         OPT_PTR(interface_shells);
         OPT_PTR(layer_height);
-        OPT_PTR(exact_last_layer_height);
+        OPT_PTR(model_precision);
         OPT_PTR(raft_layers);
         OPT_PTR(seam_position);
         OPT_PTR(seam_travel);

src/libslic3r/PrintObject.cpp

@@ -813,7 +813,6 @@ void PrintObject::tag_under_bridge() {
                             for (ExPolygon poly_inter : dense_polys) area_dense += poly_inter.area();
                             double area_sparse = 0;
                             for (ExPolygon poly_inter : sparse_polys) area_sparse += poly_inter.area();
-                            std::cout << "need to split? " << area_sparse << " > " << area_dense << " * " << COEFF_SPLIT << "\n";
                             if (area_sparse > area_dense * COEFF_SPLIT) {
                                 //split
                                 dense_polys = union_ex(dense_polys);
@@ -1913,27 +1912,27 @@ end:
 
 void PrintObject::_offsetHoles(float hole_delta, LayerRegion *layerm) {
     if (hole_delta != 0.f) {
+        std::cout << "offset_hole z="<<layerm->layer()->id()<<"\n";
         ExPolygons polys = to_expolygons(std::move(layerm->slices.surfaces));
         ExPolygons new_polys;
-        for (ExPolygon ex_poly : polys) {
+        for (const ExPolygon &ex_poly : polys) {
             ExPolygon new_ex_poly(ex_poly);
             new_ex_poly.holes.clear();
-            for (Polygon hole : ex_poly.holes) {
+            for (const Polygon &hole : ex_poly.holes) {
                 //check if convex to reduce it
                 // check whether first point forms a convex angle
+                //note: we allow a deviation of 5.7° (0.01rad = 0.57°)
                 bool ok = true;
-                ok = (hole.points.front().ccw_angle(hole.points.back(), *(hole.points.begin() + 1)) <= PI + 0.001);
+                ok = (hole.points.front().ccw_angle(hole.points.back(), *(hole.points.begin() + 1)) <= PI + 0.1);
-                   
-                
                 // check whether points 1..(n-1) form convex angles
                 if (ok)
                     for (Points::const_iterator p = hole.points.begin() + 1; p != hole.points.end() - 1; ++p) {
-                        ok = (p->ccw_angle(*(p - 1), *(p + 1)) <= PI + 0.001);
+                        ok = (p->ccw_angle(*(p - 1), *(p + 1)) <= PI + 0.1);
                         if (!ok) break;
                     }
 
                 // check whether last point forms a convex angle
-                ok &= (hole.points.back().ccw_angle(*(hole.points.end() - 2), hole.points.front()) <= PI + 0.001);
+                ok &= (hole.points.back().ccw_angle(*(hole.points.end() - 2), hole.points.front()) <= PI + 0.1);
 
                 if (ok) {
                     for (Polygon newHole : offset(hole, -hole_delta)) {
@@ -1941,8 +1940,9 @@ void PrintObject::_offsetHoles(float hole_delta, LayerRegion *layerm) {
                         newHole.make_clockwise();
                         new_ex_poly.holes.push_back(newHole);
                     }
-                } else
+                } else {
                     new_ex_poly.holes.push_back(hole);
+                }
             }
             new_polys.push_back(new_ex_poly);
         }
@@ -2007,11 +2007,11 @@ std::vector<ExPolygons> PrintObject::_slice_volumes(const std::vector<float> &z,
             // apply XY shift
             mesh.translate(- unscale<float>(m_copies_shift(0)), - unscale<float>(m_copies_shift(1)), 0);
             // perform actual slicing
-            TriangleMeshSlicer mslicer;
+            TriangleMeshSlicer mslicer(float(m_config.slice_closing_radius.value), float(m_config.model_precision.value));
             const Print *print = this->print();
             auto callback = TriangleMeshSlicer::throw_on_cancel_callback_type([print](){print->throw_if_canceled();});
             mslicer.init(&mesh, callback);
-			mslicer.slice(z, float(m_config.slice_closing_radius.value), &layers, callback);
+			mslicer.slice(z, &layers, callback);
             m_print->throw_if_canceled();
         }
     }

src/libslic3r/SLA/SLABasePool.cpp

@@ -561,7 +561,7 @@ void base_plate(const TriangleMesh &mesh, ExPolygons &output, float h,
         heights.emplace_back(hi);
 
     std::vector<ExPolygons> out; out.reserve(size_t(std::ceil(h/layerh)));
-    slicer.slice(heights, 0.f, &out, thrfn);
+    slicer.slice(heights, &out, thrfn);
 
     size_t count = 0; for(auto& o : out) count += o.size();
 

src/libslic3r/SLA/SLASupportTree.cpp

@@ -2105,7 +2105,7 @@ SlicedSupports SLASupportTree::slice(float layerh, float init_layerh) const
     fullmesh.merge(get_pad());
     TriangleMeshSlicer slicer(&fullmesh);
     SlicedSupports ret;
-    slicer.slice(heights, 0.f, &ret, get().ctl().cancelfn);
+    slicer.slice(heights, &ret, get().ctl().cancelfn);
 
     return ret;
 }

src/libslic3r/SLAPrint.cpp

@@ -629,7 +629,8 @@ void SLAPrint::process()
         double lh = po.m_config.layer_height.getFloat();
 
         TriangleMesh mesh = po.transformed_mesh();
-        TriangleMeshSlicer slicer(&mesh);
+        TriangleMeshSlicer slicer(float(po.config().slice_closing_radius.value),0);
+        slicer.init(&mesh, [](){});
 
         // The 1D grid heights
         std::vector<float> heights = calculate_heights(mesh.bounding_box(),
@@ -637,7 +638,7 @@ void SLAPrint::process()
                                                        ilh, float(lh));
 
         auto& layers = po.m_model_slices; layers.clear();
-		slicer.slice(heights, float(po.config().slice_closing_radius.value), &layers, [this](){ throw_if_canceled(); });
+		slicer.slice(heights, &layers, [this](){ throw_if_canceled(); });
     };
 
     // In this step we check the slices, identify island and cover them with

src/libslic3r/TriangleMesh.cpp

@@ -852,7 +852,7 @@ void TriangleMeshSlicer::_slice_do(size_t facet_idx, std::vector<IntersectionLin
     }
 }
 
-void TriangleMeshSlicer::slice(const std::vector<float> &z, const float closing_radius, std::vector<ExPolygons>* layers, throw_on_cancel_callback_type throw_on_cancel) const
+void TriangleMeshSlicer::slice(const std::vector<float> &z, std::vector<ExPolygons>* layers, throw_on_cancel_callback_type throw_on_cancel) const
 {
     std::vector<Polygons> layers_p;
     this->slice(z, &layers_p, throw_on_cancel);
@@ -861,13 +861,13 @@ void TriangleMeshSlicer::slice(const std::vector<float> &z, const float closing_
 	layers->resize(z.size());
 	tbb::parallel_for(
 		tbb::blocked_range<size_t>(0, z.size()),
-		[&layers_p, closing_radius, layers, throw_on_cancel, this](const tbb::blocked_range<size_t>& range) {
+		[&layers_p, layers, throw_on_cancel, this](const tbb::blocked_range<size_t>& range) {
     		for (size_t layer_id = range.begin(); layer_id < range.end(); ++ layer_id) {
 #ifdef SLIC3R_TRIANGLEMESH_DEBUG
                 printf("Layer " PRINTF_ZU " (slice_z = %.2f):\n", layer_id, z[layer_id]);
 #endif
                 throw_on_cancel();
-    			this->make_expolygons(layers_p[layer_id], closing_radius, &(*layers)[layer_id]);
+    			this->make_expolygons(layers_p[layer_id], &(*layers)[layer_id]);
     		}
     	});
 	BOOST_LOG_TRIVIAL(debug) << "TriangleMeshSlicer::make_expolygons in parallel - end";
@@ -1002,7 +1002,7 @@ TriangleMeshSlicer::FacetSliceType TriangleMeshSlicer::slice_facet(
         line_out->a_id       = points[1].point_id;
         line_out->b_id       = points[0].point_id;
         line_out->edge_a_id  = points[1].edge_id;
-        line_out->edge_b_id  = points[0].edge_id;
+        line_out->edge_b_id = points[0].edge_id;
         // Not a zero lenght edge.
         //FIXME slice_facet() may create zero length edges due to rounding of doubles into coord_t.
         //assert(line_out->a != line_out->b);
@@ -1184,7 +1184,7 @@ static void chain_lines_by_triangle_connectivity(std::vector<IntersectionLine> &
             if (next_line == nullptr) {
                 // Check whether we closed this loop.
                 if ((first_line->edge_a_id != -1 && first_line->edge_a_id == last_line->edge_b_id) || 
-                    (first_line->a_id      != -1 && first_line->a_id      == last_line->b_id)) {
+                    (first_line->a_id != -1 && first_line->a_id == last_line->b_id)) {
                     // The current loop is complete. Add it to the output.
                     loops.emplace_back(std::move(loop_pts));
                     #ifdef SLIC3R_TRIANGLEMESH_DEBUG
@@ -1600,7 +1600,7 @@ void TriangleMeshSlicer::make_expolygons_simple(std::vector<IntersectionLine> &l
 #endif
 }
 
-void TriangleMeshSlicer::make_expolygons(const Polygons &loops, const float closing_radius, ExPolygons* slices) const
+void TriangleMeshSlicer::make_expolygons(const Polygons &loops, ExPolygons* slices) const
 {
     /*
         Input loops are not suitable for evenodd nor nonzero fill types, as we might get
@@ -1651,11 +1651,19 @@ void TriangleMeshSlicer::make_expolygons(const Polygons &loops, const float clos
     //        p_slices = diff(p_slices, *loop);
     //}
 
+    //remove point in the same plane (have to do that before the safety offset to avoid workgin on a distored polygon)
+    Polygons filered_polys = loops;
+    if (this->model_precision > 0){
+        for (Polygon &hole : filered_polys){
+            hole.remove_colinear_points(scale_(this->model_precision));
+        }
+    }
+
     // Perform a safety offset to merge very close facets (TODO: find test case for this)
     // 0.0499 comes from https://github.com/slic3r/Slic3r/issues/959
 //    double safety_offset = scale_(0.0499);
     // 0.0001 is set to satisfy GH #520, #1029, #1364
-    double safety_offset = scale_(closing_radius);
+    double safety_offset = scale_(this->closing_radius);
 
     /* The following line is commented out because it can generate wrong polygons,
        see for example issue #661 */
@@ -1671,16 +1679,16 @@ void TriangleMeshSlicer::make_expolygons(const Polygons &loops, const float clos
     
     // append to the supplied collection
     if (safety_offset > 0)
-    expolygons_append(*slices, offset2_ex(union_(loops, false), +safety_offset, -safety_offset));
+        expolygons_append(*slices, offset2_ex(union_(filered_polys, false), +safety_offset, -safety_offset));
     else
-        expolygons_append(*slices, union_ex(loops, false));
+        expolygons_append(*slices, union_ex(filered_polys, false));
 }
 
-void TriangleMeshSlicer::make_expolygons(std::vector<IntersectionLine> &lines, const float closing_radius, ExPolygons* slices) const
+void TriangleMeshSlicer::make_expolygons(std::vector<IntersectionLine> &lines, ExPolygons* slices) const
 {
     Polygons pp;
     this->make_loops(lines, &pp);
-    this->make_expolygons(pp, closing_radius, slices);
+    this->make_expolygons(pp, slices);
 }
 
 void TriangleMeshSlicer::cut(float z, TriangleMesh* upper, TriangleMesh* lower) const

src/libslic3r/TriangleMesh.hpp

@@ -159,13 +159,16 @@ typedef std::vector<IntersectionLine*> IntersectionLinePtrs;
 class TriangleMeshSlicer
 {
 public:
+    float closing_radius;
+    float model_precision;
+
     typedef std::function<void()> throw_on_cancel_callback_type;
-    TriangleMeshSlicer() : mesh(nullptr) {}
+    TriangleMeshSlicer(float closing_radius, float model_precision) : mesh(nullptr), closing_radius(closing_radius), model_precision(model_precision) {}
     // Not quite nice, but the constructor and init() methods require non-const mesh pointer to be able to call mesh->require_shared_vertices()
-	TriangleMeshSlicer(TriangleMesh* mesh) { this->init(mesh, [](){}); }
+    TriangleMeshSlicer(TriangleMesh* mesh) { this->init(mesh, [](){}); }
     void init(TriangleMesh *mesh, throw_on_cancel_callback_type throw_on_cancel);
     void slice(const std::vector<float> &z, std::vector<Polygons>* layers, throw_on_cancel_callback_type throw_on_cancel) const;
-    void slice(const std::vector<float> &z, const float closing_radius, std::vector<ExPolygons>* layers, throw_on_cancel_callback_type throw_on_cancel) const;
+    void slice(const std::vector<float> &z, std::vector<ExPolygons>* layers, throw_on_cancel_callback_type throw_on_cancel) const;
     enum FacetSliceType {
         NoSlice = 0,
         Slicing = 1,
@@ -184,9 +187,9 @@ private:
 
     void _slice_do(size_t facet_idx, std::vector<IntersectionLines>* lines, boost::mutex* lines_mutex, const std::vector<float> &z) const;
     void make_loops(std::vector<IntersectionLine> &lines, Polygons* loops) const;
-    void make_expolygons(const Polygons &loops, const float closing_radius, ExPolygons* slices) const;
+    void make_expolygons(const Polygons &loops, ExPolygons* slices) const;
     void make_expolygons_simple(std::vector<IntersectionLine> &lines, ExPolygons* slices) const;
-    void make_expolygons(std::vector<IntersectionLine> &lines, const float closing_radius, ExPolygons* slices) const;
+    void make_expolygons(std::vector<IntersectionLine> &lines, ExPolygons* slices) const;
 };
 
 TriangleMesh make_cube(double x, double y, double z);

src/slic3r/GUI/Preset.cpp

@@ -402,6 +402,7 @@ const std::vector<std::string>& Preset::print_options()
         , "first_layer_infill_speed"
         , "thin_walls_min_width"
         , "thin_walls_overlap"
+        , "model_precision"
     };
     return s_opts;
 }

src/slic3r/GUI/Tab.cpp

@@ -1179,6 +1179,7 @@ void TabPrint::build()
 		optgroup = page->new_optgroup(_(L("Other")));
         optgroup->append_single_option_line("clip_multipart_objects");
 		optgroup->append_single_option_line("resolution");
+        optgroup->append_single_option_line("model_precision");
 
 	page = add_options_page(_(L("Output options")), "page_white_go.png");
 		optgroup = page->new_optgroup(_(L("Sequential printing")));