diff --git a/src/libslic3r/CMakeLists.txt b/src/libslic3r/CMakeLists.txt
index a342da831..0a0062a75 100644
--- a/src/libslic3r/CMakeLists.txt
+++ b/src/libslic3r/CMakeLists.txt
@@ -275,6 +275,8 @@ set(SLIC3R_SOURCES
     TriangleSelector.hpp
     TriangleSetSampling.cpp
     TriangleSetSampling.hpp
+    TriangleSelectorWrapper.cpp
+    TriangleSelectorWrapper.hpp
     MTUtils.hpp
     Zipper.hpp
     Zipper.cpp
diff --git a/src/libslic3r/PrintObject.cpp b/src/libslic3r/PrintObject.cpp
index 4bcf74fe5..cf6f168df 100644
--- a/src/libslic3r/PrintObject.cpp
+++ b/src/libslic3r/PrintObject.cpp
@@ -402,12 +402,38 @@ void PrintObject::find_supportable_issues()
         BOOST_LOG_TRIVIAL(debug)
         << "Searching supportable issues - start";
         //TODO status number?
-        m_print->set_status(70, L("Searching supportable issues"));
-
-        if (this->has_support()) {
+        m_print->set_status(75, L("Searching supportable issues"));
 
+        if (!this->m_config.support_material) {
+            std::vector<size_t> problematic_layers = SupportableIssues::quick_search(this);
+            if (!problematic_layers.empty()){
+                //TODO report problems
+            }
         } else {
-            SupportableIssues::quick_search(this);
+            SupportableIssues::Issues issues = SupportableIssues::full_search(this);
+            if (!issues.supports_nedded.empty()) {
+                auto obj_transform = this->trafo_centered();
+                for (ModelVolume *model_volume : this->model_object()->volumes) {
+                    if (model_volume->type() == ModelVolumeType::MODEL_PART) {
+                        Transform3d model_transformation = model_volume->get_matrix();
+                        Transform3d inv_transform = (obj_transform * model_transformation).inverse();
+                        TriangleSelectorWrapper selector { model_volume->mesh() };
+
+                        for (const Vec3f &support_point : issues.supports_nedded) {
+                            selector.enforce_spot(Vec3f(inv_transform.cast<float>() * support_point), 1.0f);
+                        }
+
+                        model_volume->supported_facets.set(selector.selector);
+
+#if 1
+                        indexed_triangle_set copy = model_volume->mesh().its;
+                        its_transform(copy, obj_transform * model_transformation);
+                        its_write_obj(copy,
+                                debug_out_path(("model" + std::to_string(model_volume->id().id) + ".obj").c_str()).c_str());
+#endif
+                    }
+                }
+            }
         }
 
         m_print->throw_if_canceled();
@@ -417,6 +443,7 @@ void PrintObject::find_supportable_issues()
     }
 }
 
+
 void PrintObject::generate_support_material()
 {
     if (this->set_started(posSupportMaterial)) {
diff --git a/src/libslic3r/SupportableIssuesSearch.cpp b/src/libslic3r/SupportableIssuesSearch.cpp
index bace1aea0..cdd3130a0 100644
--- a/src/libslic3r/SupportableIssuesSearch.cpp
+++ b/src/libslic3r/SupportableIssuesSearch.cpp
@@ -4,18 +4,31 @@
 #include "tbb/blocked_range.h"
 #include "tbb/parallel_reduce.h"
 #include <boost/log/trivial.hpp>
+#include <cmath>
 
 #include "libslic3r/Layer.hpp"
 #include "libslic3r/EdgeGrid.hpp"
 #include "libslic3r/ClipperUtils.hpp"
 
+#define DEBUG_FILES
+
+#ifdef DEBUG_FILES
+#include <boost/nowide/cstdio.hpp>
+#endif
+
 namespace Slic3r {
 namespace SupportableIssues {
 
-struct Params {
-    float bridge_distance = 5.0f;
-    float printable_protrusion_distance = 1.0f;
-};
+void Issues::add(const Issues &layer_issues) {
+    supports_nedded.insert(supports_nedded.end(),
+            layer_issues.supports_nedded.begin(), layer_issues.supports_nedded.end());
+    curling_up.insert(curling_up.end(), layer_issues.curling_up.begin(),
+            layer_issues.curling_up.end());
+}
+
+bool Issues::empty() const {
+    return supports_nedded.empty() && curling_up.empty();
+}
 
 namespace Impl {
 
@@ -34,62 +47,218 @@ struct EdgeGridWrapper {
     }
     EdgeGrid::Grid grid;
     ExPolygons ex_polys;
-}
-;
+};
 
-EdgeGridWrapper compute_layer_merged_edge_grid(const Layer *layer) {
-    static const float eps = float(scale_(layer->object()->config().slice_closing_radius.value));
-    // merge with offset
-    ExPolygons merged = layer->merged(eps);
-    // ofsset back
-    ExPolygons layer_outline = offset_ex(merged, -eps);
+#ifdef DEBUG_FILES
+void debug_export(Issues issues, std::string file_name) {
+    Slic3r::CNumericLocalesSetter locales_setter;
 
-    float min_region_flow_width { };
-    for (const auto *region : layer->regions()) {
-        min_region_flow_width = std::max(min_region_flow_width, region->flow(FlowRole::frExternalPerimeter).width());
-    }
-    std::cout << "min_region_flow_width: " << min_region_flow_width << std::endl;
-    return EdgeGridWrapper(scale_(min_region_flow_width), layer_outline);
-}
-
-void check_extrusion_entity_stability(const ExtrusionEntity *entity, const EdgeGridWrapper &supported_grid,
-        const Params &params) {
-    if (entity->is_collection()){
-        for (const auto* e: static_cast<ExtrusionEntityCollection>(entity).entities){
-            check_extrusion_entity_stability(e, supported_grid, params);
+    {
+        FILE *fp = boost::nowide::fopen(debug_out_path((file_name + "_supports.obj").c_str()).c_str(), "w");
+        if (fp == nullptr) {
+            BOOST_LOG_TRIVIAL(error)
+            << "Debug files: Couldn't open " << file_name << " for writing";
+            return;
         }
-    } else { //single extrusion path, with possible varying parameters
-        entity->as_polyline().points;
-    }
 
+        for (size_t i = 0; i < issues.supports_nedded.size(); ++i) {
+            fprintf(fp, "v %f %f %f  %f %f %f\n",
+                    issues.supports_nedded[i](0), issues.supports_nedded[i](1), issues.supports_nedded[i](2),
+                    1.0, 0.0, 0.0
+                    );
+        }
+
+        fclose(fp);
+    }
+    {
+        FILE *fp = boost::nowide::fopen(debug_out_path((file_name + "_curling.obj").c_str()).c_str(), "w");
+        if (fp == nullptr) {
+            BOOST_LOG_TRIVIAL(error)
+            << "Debug files: Couldn't open " << file_name << " for writing";
+            return;
+        }
+
+        for (size_t i = 0; i < issues.curling_up.size(); ++i) {
+            fprintf(fp, "v %f %f %f  %f %f %f\n",
+                    issues.curling_up[i](0), issues.curling_up[i](1), issues.curling_up[i](2),
+                    0.0, 1.0, 0.0
+                    );
+        }
+        fclose(fp);
+    }
 
 }
+#endif
 
-void check_layer_stability(const PrintObject *po, size_t layer_idx, const Params &params) {
-    if (layer_idx == 0) {
-        // first layer is usually ok
-        return;
+EdgeGridWrapper compute_layer_edge_grid(const Layer *layer) {
+    float min_region_flow_width { 1.0f };
+    for (const auto *region : layer->regions()) {
+        min_region_flow_width = std::min(min_region_flow_width, region->flow(FlowRole::frExternalPerimeter).width());
     }
-    const Layer *layer = po->get_layer(layer_idx);
-    const Layer *prev_layer = layer->lower_layer;
-    EdgeGridWrapper supported_grid = compute_layer_merged_edge_grid(prev_layer);
-
+    ExPolygons ex_polygons;
     for (const LayerRegion *layer_region : layer->regions()) {
-        coordf_t flow_width = coordf_t(
-                scale_(layer_region->flow(FlowRole::frExternalPerimeter).width()));
         for (const ExtrusionEntity *ex_entity : layer_region->perimeters.entities) {
             for (const ExtrusionEntity *perimeter : static_cast<const ExtrusionEntityCollection*>(ex_entity)->entities) {
                 if (perimeter->role() == ExtrusionRole::erExternalPerimeter) {
-                    check_extrusion_entity_stability(perimeter, supported_grid, params);
+                    ex_polygons.push_back(ExPolygon { perimeter->as_polyline().points });
                 } // ex_perimeter
             } // perimeter
         } // ex_entity
     }
+
+    return EdgeGridWrapper(scale_(min_region_flow_width), ex_polygons);
+}
+
+Issues check_extrusion_entity_stability(const ExtrusionEntity *entity, size_t layer_idx,
+        float slice_z,
+        coordf_t flow_width,
+        const EdgeGridWrapper &supported_grid,
+        const Params &params) {
+
+    Issues issues { };
+    if (entity->is_collection()) {
+        for (const auto *e : static_cast<const ExtrusionEntityCollection*>(entity)->entities) {
+            issues.add(check_extrusion_entity_stability(e, layer_idx, slice_z, flow_width, supported_grid, params));
+        }
+    } else { //single extrusion path, with possible varying parameters
+        Points points = entity->as_polyline().points;
+        float unsupported_distance = params.bridge_distance + 1.0f;
+        float curvature = 0;
+        float max_curvature = 0;
+        Vec2f tmp = unscale(points[0]).cast<float>();
+        Vec3f prev_point = Vec3f(tmp.x(), tmp.y(), slice_z);
+
+        for (size_t point_index = 0; point_index < points.size(); ++point_index) {
+            std::cout << "index: " << point_index << "  dist: " << unsupported_distance << "  curvature: "
+                    << curvature << "  max curvature: " << max_curvature << std::endl;
+
+            Vec2f tmp = unscale(points[point_index]).cast<float>();
+            Vec3f u_point = Vec3f(tmp.x(), tmp.y(), slice_z);
+
+            coordf_t dist_from_prev_layer { 0 };
+            if (!supported_grid.grid.signed_distance(points[point_index], flow_width, dist_from_prev_layer)) {
+                issues.supports_nedded.push_back(u_point);
+                continue;
+            }
+
+            constexpr float limit_overlap_factor = 0.5;
+
+            if (dist_from_prev_layer > flow_width) { //unsupported
+                std::cout << "index: " << point_index << "  unsupported " << std::endl;
+                unsupported_distance += (u_point - prev_point).norm();
+            } else {
+                std::cout << "index: " << point_index << "  grounded " << std::endl;
+                unsupported_distance = 0;
+            }
+
+            std::cout << "index: " << point_index << "  dfromprev: " << dist_from_prev_layer << std::endl;
+
+            if (dist_from_prev_layer > flow_width * limit_overlap_factor && point_index < points.size() - 1) {
+                const Vec2f v1 = (u_point - prev_point).head<2>();
+                const Vec2f v2 = unscale(points[point_index + 1]).cast<float>() - u_point.head<2>();
+                float dot = v1(0) * v2(0) + v1(1) * v2(1);
+                float cross = v1(0) * v2(1) - v1(1) * v2(0);
+                float angle = float(atan2(float(cross), float(dot)));
+
+                std::cout << "index: " << point_index << "  angle: " << angle << std::endl;
+
+                curvature += angle;
+                max_curvature = std::max(abs(curvature), max_curvature);
+            }
+
+            if (!(dist_from_prev_layer > flow_width * limit_overlap_factor)) {
+                std::cout << "index: " << point_index << "  reset curvature" << std::endl;
+                max_curvature = 0;
+                curvature = 0;
+            }
+
+            if (unsupported_distance > params.bridge_distance / (1 + int(max_curvature * 9 / PI))) {
+                issues.supports_nedded.push_back(u_point);
+                unsupported_distance = 0;
+                curvature = 0;
+                max_curvature = 0;
+            }
+
+            if (max_curvature / (PI * unsupported_distance) > params.limit_curvature) {
+                issues.curling_up.push_back(u_point);
+                curvature = 0;
+                max_curvature = 0;
+            }
+
+            prev_point = u_point;
+        }
+    }
+    return issues;
+}
+
+//TODO needs revision
+coordf_t get_flow_width(const LayerRegion *region, ExtrusionRole role) {
+    switch (role) {
+        case ExtrusionRole::erBridgeInfill:
+            return region->flow(FlowRole::frExternalPerimeter).scaled_width();
+        case ExtrusionRole::erExternalPerimeter:
+            return region->flow(FlowRole::frExternalPerimeter).scaled_width();
+        case ExtrusionRole::erGapFill:
+            return region->flow(FlowRole::frInfill).scaled_width();
+        case ExtrusionRole::erPerimeter:
+            return region->flow(FlowRole::frPerimeter).scaled_width();
+        case ExtrusionRole::erSolidInfill:
+            return region->flow(FlowRole::frSolidInfill).scaled_width();
+        default:
+            return region->flow(FlowRole::frExternalPerimeter).scaled_width();
+    }
+}
+
+Issues check_layer_stability(const PrintObject *po, size_t layer_idx, bool full_check, const Params &params) {
+    std::cout << "Checking: " << layer_idx << std::endl;
+    if (layer_idx == 0) {
+        // first layer is usually ok
+        return {};
+    }
+    const Layer *layer = po->get_layer(layer_idx);
+    EdgeGridWrapper supported_grid = compute_layer_edge_grid(layer->lower_layer);
+
+    Issues issues { };
+    if (full_check) {
+        for (const LayerRegion *layer_region : layer->regions()) {
+            for (const ExtrusionEntity *ex_entity : layer_region->perimeters.entities) {
+                for (const ExtrusionEntity *perimeter : static_cast<const ExtrusionEntityCollection*>(ex_entity)->entities) {
+                    issues.add(check_extrusion_entity_stability(perimeter, layer_idx,
+                            layer->slice_z, get_flow_width(layer_region, perimeter->role()),
+                            supported_grid, params));
+                } // perimeter
+            } // ex_entity
+            for (const ExtrusionEntity *ex_entity : layer_region->fills.entities) {
+                for (const ExtrusionEntity *fill : static_cast<const ExtrusionEntityCollection*>(ex_entity)->entities) {
+                    if (fill->role() == ExtrusionRole::erGapFill || fill->role() == ExtrusionRole::erBridgeInfill) {
+                        issues.add(check_extrusion_entity_stability(fill, layer_idx,
+                                layer->slice_z, get_flow_width(layer_region, fill->role()),
+                                supported_grid, params));
+                    }
+                } // fill
+            } // ex_entity
+        } // region
+    } else { //check only external perimeters
+        for (const LayerRegion *layer_region : layer->regions()) {
+            for (const ExtrusionEntity *ex_entity : layer_region->perimeters.entities) {
+                for (const ExtrusionEntity *perimeter : static_cast<const ExtrusionEntityCollection*>(ex_entity)->entities) {
+                    if (perimeter->role() == ExtrusionRole::erExternalPerimeter) {
+                        std::cout << "checking ex perimeter " << std::endl;
+                        issues.add(check_extrusion_entity_stability(perimeter, layer_idx,
+                                layer->slice_z, get_flow_width(layer_region, perimeter->role()),
+                                supported_grid, params));
+                    }; // ex_perimeter
+                } // perimeter
+            } // ex_entity
+        } //region
+    }
+
+    return issues;
 }
 
 } //Impl End
 
-void quick_search(const PrintObject *po, const Params &params = Params { }) {
+std::vector<size_t> quick_search(const PrintObject *po, const Params &params) {
     using namespace Impl;
     std::vector<LayerDescriptor> descriptors(po->layer_count());
 
@@ -129,20 +298,75 @@ void quick_search(const PrintObject *po, const Params &params = Params { }) {
             } // thread
             );
 
-    for (size_t desc_idx = 0; desc_idx < descriptors.size(); ++desc_idx) {
+    std::vector<size_t> suspicious_layers_indices { };
+
+    for (size_t desc_idx = 1; desc_idx < descriptors.size(); ++desc_idx) {
+        const LayerDescriptor &prev = descriptors[desc_idx - 1];
         const LayerDescriptor &descriptor = descriptors[desc_idx];
+        if (descriptor.segments_count - prev.segments_count != 0
+                ||
+                std::abs(descriptor.perimeter_length - prev.perimeter_length)
+                        > params.perimeter_length_diff_tolerance ||
+                (descriptor.centroid - prev.centroid).norm() > params.centroid_offset_tolerance
+                        ) {
+            suspicious_layers_indices.push_back(desc_idx);
+        }
+#ifdef DEBUG_FILES
         std::cout << "SIS layer idx: " << desc_idx << " reg count: " << descriptor.segments_count << " len: "
                 << descriptor.perimeter_length <<
                 " centroid: " << descriptor.centroid.x() << " | " << descriptor.centroid.y() << std::endl;
-        if (desc_idx > 0) {
-            const LayerDescriptor &prev = descriptors[desc_idx - 1];
-            std::cout << "SIS diff: " << desc_idx << " reg count: "
-                    << (int(descriptor.segments_count) - int(prev.segments_count)) <<
-                    " len: " << (descriptor.perimeter_length - prev.perimeter_length) <<
-                    " centroid: " << (descriptor.centroid - prev.centroid).norm() << std::endl;
+        std::cout << "SIS diff: " << desc_idx << " reg count: "
+                << (int(descriptor.segments_count) - int(prev.segments_count)) <<
+                " len: " << (descriptor.perimeter_length - prev.perimeter_length) <<
+                " centroid: " << (descriptor.centroid - prev.centroid).norm() << std::endl;
+#endif
+    }
+
+    std::vector<bool> layer_needs_supports(suspicious_layers_indices.size(), false);
+    tbb::parallel_for(tbb::blocked_range<size_t>(0, suspicious_layers_indices.size()),
+            [&](tbb::blocked_range<size_t> r) {
+                for (size_t suspicious_index = r.begin(); suspicious_index < r.end(); ++suspicious_index) {
+                    auto layer_issues = check_layer_stability(po, suspicious_layers_indices[suspicious_index],
+                            false,
+                            params);
+                    if (!layer_issues.supports_nedded.empty()) {
+                        layer_needs_supports[suspicious_index] = true;
+                    }
+                }
+            });
+
+    std::vector<size_t> problematic_layers;
+
+    for (size_t index = suspicious_layers_indices.size() - 1; index <= 0; ++index) {
+        if (!layer_needs_supports[index]) {
+            problematic_layers.push_back(suspicious_layers_indices[index]);
+        }
+    }
+    return problematic_layers;
+}
+
+Issues full_search(const PrintObject *po, const Params &params) {
+    using namespace Impl;
+    Issues issues { };
+    for (size_t layer_idx = 1; layer_idx < po->layer_count(); ++layer_idx) {
+        auto layer_issues = check_layer_stability(po, layer_idx, true, params);
+        if (!layer_issues.empty()) {
+            issues.add(layer_issues);
         }
     }
 
+#ifdef DEBUG_FILES
+    Impl::debug_export(issues, "issues");
+#endif
+
+//    tbb::parallel_for(tbb::blocked_range<size_t>(0, suspicious_layers_indices.size()),
+//            [&](tbb::blocked_range<size_t> r) {
+//                for (size_t layer_idx = r.begin(); layer_idx < r.end(); ++layer_idx) {
+//                    check_layer_stability(po, suspicious_layers_indices[layer_idx], params);
+//                }
+//            });
+
+    return issues;
 }
 
 }
diff --git a/src/libslic3r/SupportableIssuesSearch.hpp b/src/libslic3r/SupportableIssuesSearch.hpp
index dbec52aff..22289c923 100644
--- a/src/libslic3r/SupportableIssuesSearch.hpp
+++ b/src/libslic3r/SupportableIssuesSearch.hpp
@@ -7,7 +7,25 @@ namespace Slic3r {
 
 namespace SupportableIssues {
 
-void quick_search(const PrintObject *po);
+struct Params {
+    float bridge_distance = 5.0f;
+    float limit_curvature = 0.25f;
+
+    float perimeter_length_diff_tolerance = 8.0f;
+    float centroid_offset_tolerance = 1.0f;
+};
+
+
+struct Issues {
+    std::vector<Vec3f> supports_nedded;
+    std::vector<Vec3f> curling_up;
+
+    void add(const Issues &layer_issues);
+    bool empty() const;
+};
+
+std::vector<size_t> quick_search(const PrintObject *po, const Params &params = Params { });
+Issues full_search(const PrintObject *po, const Params &params = Params { });
 
 }
 
diff --git a/src/libslic3r/TriangleSelectorWrapper.cpp b/src/libslic3r/TriangleSelectorWrapper.cpp
new file mode 100644
index 000000000..8b1378917
--- /dev/null
+++ b/src/libslic3r/TriangleSelectorWrapper.cpp
@@ -0,0 +1 @@
+
diff --git a/src/libslic3r/TriangleSelectorWrapper.hpp b/src/libslic3r/TriangleSelectorWrapper.hpp
new file mode 100644
index 000000000..f818d8be2
--- /dev/null
+++ b/src/libslic3r/TriangleSelectorWrapper.hpp
@@ -0,0 +1,42 @@
+#ifndef SRC_LIBSLIC3R_TRIANGLESELECTORWRAPPER_HPP_
+#define SRC_LIBSLIC3R_TRIANGLESELECTORWRAPPER_HPP_
+
+#include <memory>
+
+#include "TriangleSelector.hpp"
+#include "AABBTreeIndirect.hpp"
+
+namespace Slic3r {
+
+class TriangleSelectorWrapper {
+public:
+    const TriangleMesh &mesh;
+    TriangleSelector selector;
+    AABBTreeIndirect::Tree<3, float> triangles_tree;
+
+    TriangleSelectorWrapper(const TriangleMesh &mesh) :
+            mesh(mesh), selector(mesh), triangles_tree(AABBTreeIndirect::build_aabb_tree_over_indexed_triangle_set(mesh.its.vertices, mesh.its.indices)) {
+
+    }
+
+    void enforce_spot(const Vec3f &point, float radius) {
+        size_t hit_face_index;
+        Vec3f hit_point;
+        auto dist = AABBTreeIndirect::squared_distance_to_indexed_triangle_set(mesh.its.vertices, mesh.its.indices,
+                triangles_tree,
+                point, hit_face_index, hit_point);
+        if (dist < 0 || dist > radius)
+            return;
+
+        std::unique_ptr<TriangleSelector::Cursor> cursor = std::make_unique<TriangleSelector::Sphere>(point, point,
+                radius, Transform3d::Identity(), TriangleSelector::ClippingPlane { });
+
+        selector.select_patch(hit_face_index, std::move(cursor), EnforcerBlockerType::ENFORCER, Transform3d::Identity(), true,
+                0.0f);
+    }
+
+};
+
+}
+
+#endif /* SRC_LIBSLIC3R_TRIANGLESELECTORWRAPPER_HPP_ */