Improved handling of excessive extrusion width values (too small

or too big).
Fixes std: bad_alloc #2715

src/libslic3r/Flow.cpp

@@ -76,10 +76,14 @@ float Flow::spacing() const
         return this->width + BRIDGE_EXTRA_SPACING;
     // rectangle with semicircles at the ends
     float min_flow_spacing = this->width - this->height * (1. - 0.25 * PI);
-    return this->width - PERIMETER_LINE_OVERLAP_FACTOR * (this->width - min_flow_spacing);
+    float res = this->width - PERIMETER_LINE_OVERLAP_FACTOR * (this->width - min_flow_spacing);
 #else
-    return float(this->bridge ? (this->width + BRIDGE_EXTRA_SPACING) : (this->width - this->height * (1. - 0.25 * PI)));
+    float res = float(this->bridge ? (this->width + BRIDGE_EXTRA_SPACING) : (this->width - this->height * (1. - 0.25 * PI)));
 #endif
+//    assert(res > 0.f);
+	if (res <= 0.f)
+		throw std::runtime_error("Flow::spacing() produced negative spacing. Did you set some extrusion width too small?");
+	return res;
 }
 
 // This method returns the centerline spacing between an extrusion using this
@@ -89,20 +93,26 @@ float Flow::spacing(const Flow &other) const
 {
     assert(this->height == other.height);
     assert(this->bridge == other.bridge);
-    return float(this->bridge ? 
+    float res = float(this->bridge ? 
         0.5 * this->width + 0.5 * other.width + BRIDGE_EXTRA_SPACING :
         0.5 * this->spacing() + 0.5 * other.spacing());
+//    assert(res > 0.f);
+	if (res <= 0.f)
+		throw std::runtime_error("Flow::spacing() produced negative spacing. Did you set some extrusion width too small?");
+	return res;
 }
 
 // This method returns extrusion volume per head move unit.
 double Flow::mm3_per_mm() const 
 {
-    double res = this->bridge ?
+    float res = this->bridge ?
         // Area of a circle with dmr of this->width.
         (this->width * this->width) * 0.25 * PI :
         // Rectangle with semicircles at the ends. ~ h (w - 0.215 h)
         this->height * (this->width - this->height * (1. - 0.25 * PI));
-    assert(res > 0.);
+    //assert(res > 0.);
+	if (res <= 0.)
+		throw std::runtime_error("Flow::mm3_per_mm() produced negative flow. Did you set some extrusion width too small?");
     return res;
 }
 

src/libslic3r/Print.cpp

@@ -18,6 +18,7 @@
 #include <limits>
 #include <unordered_set>
 #include <boost/filesystem/path.hpp>
+#include <boost/format.hpp>
 #include <boost/log/trivial.hpp>
 
 //! macro used to mark string used at localization,
@@ -1168,7 +1169,7 @@ std::string Print::validate() const
             bool                                has_custom_layering = false;
             std::vector<std::vector<coordf_t>>  layer_height_profiles;
             for (const PrintObject *object : m_objects) {
-                has_custom_layering = ! object->model_object()->layer_config_ranges.empty() || ! object->model_object()->layer_height_profile.empty();      // #ys_FIXME_experiment
+                has_custom_layering = ! object->model_object()->layer_config_ranges.empty() || ! object->model_object()->layer_height_profile.empty();
                 if (has_custom_layering) {
                     layer_height_profiles.assign(m_objects.size(), std::vector<coordf_t>());
                     break;
@@ -1247,6 +1248,18 @@ std::string Print::validate() const
                 return L("One or more object were assigned an extruder that the printer does not have.");
 #endif
 
+		auto validate_extrusion_width = [min_nozzle_diameter, max_nozzle_diameter](const ConfigBase &config, const char *opt_key, double layer_height, std::string &err_msg) -> bool {
+        	double extrusion_width_min = config.get_abs_value(opt_key, min_nozzle_diameter);
+        	double extrusion_width_max = config.get_abs_value(opt_key, max_nozzle_diameter);
+        	if (extrusion_width_min <= layer_height) {
+        		err_msg = (boost::format(L("%1%=%2% mm is too low to be printable at a layer height %3% mm")) % opt_key % extrusion_width_min % layer_height).str();
+				return false;
+			} else if (extrusion_width_max >= max_nozzle_diameter * 2.) {
+				err_msg = (boost::format(L("Excessive %1%=%2% mm to be printable with a nozzle diameter %3% mm")) % opt_key % extrusion_width_max % max_nozzle_diameter).str();
+				return false;
+			}
+			return true;
+		};
         for (PrintObject *object : m_objects) {
             if (object->config().raft_layers > 0 || object->config().support_material.value) {
 				if ((object->config().support_material_extruder == 0 || object->config().support_material_interface_extruder == 0) && max_nozzle_diameter - min_nozzle_diameter > EPSILON) {
@@ -1290,8 +1303,24 @@ std::string Print::validate() const
                 return L("First layer height can't be greater than nozzle diameter");
             
             // validate layer_height
-            if (object->config().layer_height.value > min_nozzle_diameter)
+            double layer_height = object->config().layer_height.value;
+            if (layer_height > min_nozzle_diameter)
                 return L("Layer height can't be greater than nozzle diameter");
+
+            // Validate extrusion widths.
+            for (const char *opt_key : { "extrusion_width", "support_material_extrusion_width" }) {
+            	std::string err_msg;
+            	if (! validate_extrusion_width(object->config(), opt_key, layer_height, err_msg))
+            		return err_msg;
+            }
+            for (const char *opt_key : { "perimeter_extrusion_width", "external_perimeter_extrusion_width", "infill_extrusion_width", "solid_infill_extrusion_width", "top_infill_extrusion_width" }) {
+				for (size_t i = 0; i < object->region_volumes.size(); ++ i)
+            		if (! object->region_volumes[i].empty()) {
+		            	std::string err_msg;
+		            	if (! validate_extrusion_width(this->get_region(i)->config(), opt_key, layer_height, err_msg))
+		            		return err_msg;
+            		}
+            }
         }
     }
 

src/slic3r/GUI/Tab.cpp

@@ -1758,6 +1758,17 @@ void TabFilament::reload_config()
 	Tab::reload_config();
 }
 
+void TabFilament::update_volumetric_flow_preset_hints()
+{
+	wxString text;
+	try {
+		text = from_u8(PresetHints::maximum_volumetric_flow_description(*m_preset_bundle));
+	} catch (std::exception &ex) {
+		text = _(L("Volumetric flow hints not available\n\n")) + from_u8(ex.what());
+	}
+	m_volumetric_speed_description_line->SetText(text);
+}
+
 void TabFilament::update()
 {
     if (m_preset_bundle->printers.get_selected_preset().printer_technology() == ptSLA)
@@ -1767,8 +1778,7 @@ void TabFilament::update()
 
 	wxString text = from_u8(PresetHints::cooling_description(m_presets->get_edited_preset()));
 	m_cooling_description_line->SetText(text);
-	text = from_u8(PresetHints::maximum_volumetric_flow_description(*m_preset_bundle));
+	this->update_volumetric_flow_preset_hints();
-	m_volumetric_speed_description_line->SetText(text);
     Layout();
 
 	bool cooling = m_config->opt_bool("cooling", 0);
@@ -1790,7 +1800,7 @@ void TabFilament::update()
 
 void TabFilament::OnActivate()
 {
-	m_volumetric_speed_description_line->SetText(from_u8(PresetHints::maximum_volumetric_flow_description(*m_preset_bundle)));
+	this->update_volumetric_flow_preset_hints();
 	Tab::OnActivate();
 }
 

src/slic3r/GUI/Tab.hpp

@@ -340,6 +340,7 @@ class TabFilament : public Tab
 
     void            add_filament_overrides_page();
     void            update_filament_overrides_page();
+	void 			update_volumetric_flow_preset_hints();
 
     std::map<std::string, wxCheckBox*> m_overrides_options;
 public: