max_layer_height & min_layer_height now can be percent.

Also some fixes on crash that may happens when using them.

src/libslic3r/Config.hpp

@@ -1108,9 +1108,12 @@ private:
 
 struct FloatOrPercent
 {
+public:
     double  value;
     bool    percent;
 
+    double get_abs_value(double ratio) const { return percent ? value * ratio : value; }
+
 private:
     friend class cereal::access;
     template<class Archive> void serialize(Archive & ar) {ar(this->value); ar(this->percent); }

src/libslic3r/GCode.cpp

@@ -518,8 +518,10 @@ std::vector<GCode::LayerToPrint> GCode::collect_layers_to_print(const PrintObjec
         gap_over_supports = std::max(0., gap_over_supports);
         // Not a soluble support,
         double support_layer_height_min = 1000000.;
-        for (auto lh : object.print()->config().min_layer_height.values)
-            support_layer_height_min = std::min(support_layer_height_min, std::max(0.01, lh));
+        const ConfigOptionFloatsOrPercents& min_layer_height = object.print()->config().min_layer_height;
+        const ConfigOptionFloats& nozzle_diameter = object.print()->config().nozzle_diameter;
+        for(int extr_id = 0; extr_id < min_layer_height.values.size(); ++extr_id)
+            support_layer_height_min = std::min(support_layer_height_min, std::max(nozzle_diameter.values[extr_id]/40, min_layer_height.get_abs_value(extr_id, nozzle_diameter.values[extr_id])));
         gap_over_supports += support_layer_height_min;
     }
 
@@ -2915,9 +2917,9 @@ std::string GCode::extrude_loop_vase(const ExtrusionLoop &original_loop, const s
     }
 
     //all in unscaled coordinates (hence why it's coordf_t and not coord_t)
-    const coordf_t min_height = EXTRUDER_CONFIG_WITH_DEFAULT(min_layer_height, this->m_layer->height);
+    const coordf_t min_height = m_config.min_layer_height.get_abs_value(m_writer.tool()->id(), m_config.nozzle_diameter.get_at(m_writer.tool()->id()));
     const coordf_t bot_init_z = - this->m_layer->height;
-    //const coordf_t bot_last_z = bot_init_z + this->m_layer->height - EXTRUDER_CONFIG(min_layer_height);
+    //const coordf_t bot_last_z = bot_init_z + this->m_layer->height - m_config.min_layer_height.get_abs_value(m_writer.tool()->id(), m_config.nozzle_diameter.get_at(m_writer.tool()->id()));
     const coordf_t init_z = bot_init_z + min_height;
     //const coordf_t last_z = bot_init_z + this->m_layer->height;
 
@@ -3157,7 +3159,7 @@ std::string GCode::extrude_loop(const ExtrusionLoop &original_loop, const std::s
         //but not for the first layer
         && this->m_layer->id() > 0
         //exclude if min_layer_height * 2 > layer_height (increase from 2 to 3 because it's working but uses in-between)
-        && this->m_layer->height >= EXTRUDER_CONFIG_WITH_DEFAULT(min_layer_height, 0) * 2 - EPSILON
+        && this->m_layer->height >= m_config.min_layer_height.get_abs_value(m_writer.tool()->id(), m_config.nozzle_diameter.get_at(m_writer.tool()->id())) * 2 - EPSILON
         ) {
         return extrude_loop_vase(original_loop, description, speed, lower_layer_edge_grid);
     }

src/libslic3r/GCode/ToolOrdering.cpp

@@ -349,7 +349,7 @@ void ToolOrdering::fill_wipe_tower_partitions(const PrintConfig &config, coordf_
     // Test for a raft, insert additional wipe tower layer to fill in the raft separation gap.
     double max_layer_height = std::numeric_limits<double>::max();
     for (size_t i = 0; i < config.nozzle_diameter.values.size(); ++ i) {
-        double mlh = config.max_layer_height.values[i];
+        double mlh = config.max_layer_height.get_abs_value(i, config.nozzle_diameter.values[i]);
         if (mlh == 0.)
             mlh = 0.75 * config.nozzle_diameter.values[i];
         max_layer_height = std::min(max_layer_height, mlh);

src/libslic3r/Print.cpp

@@ -1595,9 +1595,9 @@ std::pair<PrintBase::PrintValidationError, std::string> Print::validate() const
                 PrintRegion::collect_object_printing_extruders(config(), object->config(), region->config(), object_extruders);
                 double layer_height = object->config().layer_height.value;
                 for (uint16_t extruder_id : object_extruders) {
-                    double min_layer_height = config().min_layer_height.values[extruder_id];
-                    double max_layer_height = config().max_layer_height.values[extruder_id];
-                    double nozzle_diameter = config().nozzle_diameter.values[extruder_id];
+                    double nozzle_diameter = config().nozzle_diameter.get_at(extruder_id);
+                    double min_layer_height = config().min_layer_height.get_abs_value(extruder_id, nozzle_diameter);
+                    double max_layer_height = config().max_layer_height.get_abs_value(extruder_id, nozzle_diameter);
                     if (max_layer_height < EPSILON) max_layer_height = nozzle_diameter * 0.75;
                     if (min_layer_height > max_layer_height) return { PrintBase::PrintValidationError::pveWrongSettings, L("Min layer height can't be greater than Max layer height") };
                     if (max_layer_height > nozzle_diameter) return { PrintBase::PrintValidationError::pveWrongSettings, L("Max layer height can't be greater than nozzle diameter") };

src/libslic3r/PrintConfig.cpp

@@ -2732,19 +2732,21 @@ void PrintConfigDef::init_fff_params()
     def->is_vector_extruder = true;
     def->set_default_value(new ConfigOptionInts { 100 });
 
-    def = this->add("max_layer_height", coFloats);
+    def = this->add("max_layer_height", coFloatsOrPercents);
     def->label = L("Max");
     def->full_label = L("Max layer height");
     def->category = OptionCategory::general;
     def->tooltip = L("This is the highest printable layer height for this extruder, used to cap "
                    "the variable layer height and support layer height. Maximum recommended layer height "
                    "is 75% of the extrusion width to achieve reasonable inter-layer adhesion. "
-                   "If set to 0, layer height is limited to 75% of the nozzle diameter.");
-    def->sidetext = L("mm");
+                   "\nCan be a % of the nozzle diameter."
+                   "\nIf set to 0, layer height is limited to 75% of the nozzle diameter.");
+    def->sidetext = L("mm or %");
+    def->ratio_over = "nozzle_diameter";
     def->min = 0;
     def->mode = comSimple;
     def->is_vector_extruder = true;
-    def->set_default_value(new ConfigOptionFloats { 0. });
+    def->set_default_value(new ConfigOptionFloatsOrPercents{ FloatOrPercent{ 75, true} });
 
     def = this->add("max_print_speed", coFloat);
     def->label = L("Max print speed");
@@ -2824,17 +2826,19 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionBool(false));
 
-    def = this->add("min_layer_height", coFloats);
+    def = this->add("min_layer_height", coFloatsOrPercents);
     def->label = L("Min");
     def->full_label = L("Min layer height");
     def->category = OptionCategory::extruders;
     def->tooltip = L("This is the lowest printable layer height for this extruder and limits "
-                   "the resolution for variable layer height. Typical values are between 0.05 mm and 0.1 mm.");
-    def->sidetext = L("mm");
+                    "the resolution for variable layer height. Typical values are between 0.05 mm and 0.1 mm."
+                    "\nCan be a % of the nozzle diameter.");
+    def->sidetext = L("mm or %");
+    def->ratio_over = "nozzle_diameter";
     def->min = 0;
     def->mode = comSimple;
     def->is_vector_extruder = true;
-    def->set_default_value(new ConfigOptionFloats { 0.07 });
+    def->set_default_value(new ConfigOptionFloatsOrPercents{ FloatOrPercent{ 5, true} });
 
     def = this->add("min_length", coFloat);
     def->label = L("Minimum extrusion length");

src/libslic3r/PrintConfig.hpp

@@ -1339,7 +1339,7 @@ public:
     ConfigOptionInts                full_fan_speed_layer;
     ConfigOptionFloatOrPercent      infill_acceleration;
     ConfigOptionInts                max_fan_speed;
-    ConfigOptionFloats              max_layer_height;
+    ConfigOptionFloatsOrPercents    max_layer_height;
     ConfigOptionFloat               max_print_height;
     ConfigOptionPercents            max_speed_reduction;
     ConfigOptionFloats              milling_diameter;
@@ -1348,7 +1348,7 @@ public:
     //ConfigOptionPoints              milling_offset;
     //ConfigOptionFloats              milling_z_offset;
     ConfigOptionInts                min_fan_speed;
-    ConfigOptionFloats              min_layer_height;
+    ConfigOptionFloatsOrPercents    min_layer_height;
     ConfigOptionFloats              min_print_speed;
     ConfigOptionFloat               min_skirt_length;
     ConfigOptionString              notes;

src/libslic3r/Slicing.cpp

@@ -39,36 +39,40 @@ inline bool test_z_step(const coordf_t val, const coordf_t z_step) {
 }
 
 // Minimum layer height for the variable layer height algorithm.
-inline coordf_t min_layer_height_from_nozzle(const PrintConfig &print_config, int idx_nozzle)
+// idx_nozzle began at 0
+inline coordf_t min_layer_height_from_nozzle(const PrintConfig &print_config, uint16_t idx_nozzle)
 {
-    coordf_t min_layer_height = print_config.min_layer_height.get_at(idx_nozzle - 1);
+    coordf_t min_layer_height = print_config.min_layer_height.get_abs_value(idx_nozzle, print_config.nozzle_diameter.get_at(idx_nozzle));
     return check_z_step( (min_layer_height == 0.) ? (MIN_LAYER_HEIGHT_DEFAULT) : std::max(MIN_LAYER_HEIGHT, min_layer_height), print_config.z_step);
 }
 
 // Maximum layer height for the variable layer height algorithm, 3/4 of a nozzle dimaeter by default,
 // it should not be smaller than the minimum layer height.
-inline coordf_t max_layer_height_from_nozzle(const PrintConfig &print_config, int idx_nozzle)
+// idx_nozzle began at 0
+inline coordf_t max_layer_height_from_nozzle(const PrintConfig &print_config, uint16_t idx_nozzle)
 {
     coordf_t min_layer_height = min_layer_height_from_nozzle(print_config, idx_nozzle);
-    coordf_t max_layer_height = print_config.max_layer_height.get_at(idx_nozzle - 1);
-    coordf_t nozzle_dmr       = print_config.nozzle_diameter.get_at(idx_nozzle - 1);
+    coordf_t nozzle_dmr = print_config.nozzle_diameter.get_at(idx_nozzle);
+    coordf_t max_layer_height = print_config.max_layer_height.get_abs_value(idx_nozzle, nozzle_dmr);
     return check_z_step(std::max(min_layer_height, (max_layer_height == 0.) ? (0.75 * nozzle_dmr) : max_layer_height), print_config.z_step);
 }
 
 // Minimum layer height for the variable layer height algorithm.
-coordf_t Slicing::min_layer_height_from_nozzle(const DynamicPrintConfig &print_config, int idx_nozzle)
+// idx_nozzle began at 0
+coordf_t Slicing::min_layer_height_from_nozzle(const DynamicPrintConfig &print_config, uint16_t idx_nozzle)
 {
-    coordf_t min_layer_height = print_config.opt_float("min_layer_height", idx_nozzle - 1);
+    coordf_t min_layer_height = print_config.get_computed_value("min_layer_height", idx_nozzle);
     return check_z_step((min_layer_height == 0.) ? (MIN_LAYER_HEIGHT_DEFAULT) : std::max(MIN_LAYER_HEIGHT, min_layer_height), print_config.opt_float("z_step"));
 }
 
 // Maximum layer height for the variable layer height algorithm, 3/4 of a nozzle dimaeter by default,
 // it should not be smaller than the minimum layer height.
-coordf_t Slicing::max_layer_height_from_nozzle(const DynamicPrintConfig &print_config, int idx_nozzle)
+// idx_nozzle began at 0
+coordf_t Slicing::max_layer_height_from_nozzle(const DynamicPrintConfig &print_config, uint16_t idx_nozzle)
 {
     coordf_t min_layer_height = min_layer_height_from_nozzle(print_config, idx_nozzle);
-    coordf_t max_layer_height = print_config.opt_float("max_layer_height", idx_nozzle - 1);
-    coordf_t nozzle_dmr       = print_config.opt_float("nozzle_diameter", idx_nozzle - 1);
+    coordf_t max_layer_height = print_config.get_computed_value("max_layer_height", idx_nozzle);
+    coordf_t nozzle_dmr       = print_config.opt_float("nozzle_diameter", idx_nozzle);
     return check_z_step(std::max(min_layer_height, (max_layer_height == 0.) ? (0.75 * nozzle_dmr) : max_layer_height), print_config.opt_float("z_step"));
 }
 
@@ -124,18 +128,26 @@ SlicingParameters SlicingParameters::create_from_config(
     if (params.object_print_z_max < object_height) params.object_print_z_max += params.z_step;
 
     // Miniumum/maximum of the minimum layer height over all extruders.
-    params.min_layer_height = MIN_LAYER_HEIGHT;
+    params.min_layer_height = 0;
     params.max_layer_height = std::numeric_limits<double>::max();
+    params.max_suport_layer_height = 0;
     params.exact_last_layer_height = object_config.exact_last_layer_height.value;
     if (object_config.support_material.value || params.base_raft_layers > 0) {
         // Has some form of support. Add the support layers to the minimum / maximum layer height limits.
-        params.min_layer_height = std::max(
-            min_layer_height_from_nozzle(print_config, object_config.support_material_extruder), 
-            min_layer_height_from_nozzle(print_config, object_config.support_material_interface_extruder));
-        params.max_layer_height = std::min(
-            max_layer_height_from_nozzle(print_config, object_config.support_material_extruder), 
-            max_layer_height_from_nozzle(print_config, object_config.support_material_interface_extruder));
-        params.max_suport_layer_height = params.max_layer_height;
+        if (object_config.support_material_extruder > 0)
+            params.min_layer_height = std::max(params.min_layer_height,
+                min_layer_height_from_nozzle(print_config, object_config.support_material_extruder - 1));
+        if (object_config.support_material_interface_extruder > 0)
+            params.min_layer_height = std::max(params.min_layer_height,
+                min_layer_height_from_nozzle(print_config, object_config.support_material_interface_extruder - 1));
+        if (object_config.support_material_extruder > 0)
+            params.max_layer_height = std::min(params.max_layer_height,
+                max_layer_height_from_nozzle(print_config, object_config.support_material_extruder - 1));
+        if (object_config.support_material_interface_extruder > 0)
+            params.max_layer_height = std::min(params.max_layer_height,
+                max_layer_height_from_nozzle(print_config, object_config.support_material_interface_extruder - 1));
+        if (params.max_layer_height < std::numeric_limits<double>::max())
+            params.max_suport_layer_height = params.max_layer_height;
     }
     if (object_extruders.empty()) {
         params.min_layer_height = std::max(params.min_layer_height, min_layer_height_from_nozzle(print_config, 0));
@@ -151,6 +163,7 @@ SlicingParameters SlicingParameters::create_from_config(
     //apply z_step to min/max
     params.min_layer_height = check_z_step(params.min_layer_height, params.z_step);
     params.max_layer_height = check_z_step(params.max_layer_height, params.z_step);
+    if (params.max_suport_layer_height == 0) params.max_suport_layer_height = params.max_layer_height;
     params.max_suport_layer_height = check_z_step(params.max_suport_layer_height, params.z_step);
 
     if (! soluble_interface) {

src/libslic3r/Slicing.hpp

@@ -188,13 +188,13 @@ extern int generate_layer_height_texture(
     void *data, int rows, int cols, bool level_of_detail_2nd_level);
 
 namespace Slicing {
-	// Minimum layer height for the variable layer height algorithm. Nozzle index is 1 based.
-	coordf_t min_layer_height_from_nozzle(const DynamicPrintConfig &print_config, int idx_nozzle);
+	// Minimum layer height for the variable layer height algorithm. Nozzle index is 0 based.
+	coordf_t min_layer_height_from_nozzle(const DynamicPrintConfig &print_config, uint16_t idx_nozzle);
 
 	// Maximum layer height for the variable layer height algorithm, 3/4 of a nozzle dimaeter by default,
 	// it should not be smaller than the minimum layer height.
-	// Nozzle index is 1 based.
-	coordf_t max_layer_height_from_nozzle(const DynamicPrintConfig &print_config, int idx_nozzle);
+	// Nozzle index is 0 based.
+	coordf_t max_layer_height_from_nozzle(const DynamicPrintConfig &print_config, uint16_t idx_nozzle);
 } // namespace Slicing
 
 } // namespace Slic3r

src/libslic3r/SupportMaterial.cpp

@@ -152,8 +152,10 @@ PrintObjectSupportMaterial::PrintObjectSupportMaterial(const PrintObject *object
 {
     // Calculate a minimum support layer height as a minimum over all extruders, but not smaller than 10um.
     m_support_layer_height_min = 1000000.;
-    for (auto lh : m_print_config->min_layer_height.values)
-        m_support_layer_height_min = std::min(m_support_layer_height_min, std::max(0.01, lh));
+    const ConfigOptionFloatsOrPercents& min_layer_height = m_print_config->min_layer_height;
+    const ConfigOptionFloats& nozzle_diameter = m_print_config->nozzle_diameter;
+    for (int extr_id = 0; extr_id < min_layer_height.values.size(); ++extr_id)
+        m_support_layer_height_min = std::min(m_support_layer_height_min, std::max(0.01, min_layer_height.get_abs_value(extr_id, nozzle_diameter.get_at(extr_id))));
 
     if (m_object_config->support_material_interface_layers.value == 0) {
         // No interface layers allowed, print everything with the base support pattern.

src/slic3r/GUI/CalibrationBridgeDialog.cpp

@@ -150,7 +150,7 @@ void CalibrationBridgeDialog::create_geometry(std::string setting_to_test, bool
         double z_step = printer_config->option<ConfigOptionFloat>("z_step")->value;
         if (z_step == 0)
             z_step = 0.1;
-        double max_height = printer_config->option<ConfigOptionFloats>("max_layer_height")->values[0];
+        double max_height = printer_config->get_computed_value("max_layer_height",0);
         if (max_height > first_layer_height + z_step)
             for (size_t i = 0; i < nb_items; i++)
                 model.objects[objs_idx[i]]->config.set_key_value("first_layer_height", new ConfigOptionFloatOrPercent(first_layer_height + z_step, false));

src/slic3r/GUI/GLCanvas3D.cpp

@@ -461,36 +461,36 @@ void GLCanvas3D::LayersEditing::render_volumes(const GLCanvas3D& canvas, const G
         // The layer editing shader was already active.
         current_shader = nullptr;
 
-        const_cast<LayersEditing*>(this)->generate_layer_height_texture();
+    const_cast<LayersEditing*>(this)->generate_layer_height_texture();
 
-        // Uniforms were resolved, go ahead using the layer editing shader.
+    // Uniforms were resolved, go ahead using the layer editing shader.
     shader->set_uniform("z_to_texture_row", float(m_layers_texture.cells - 1) / (float(m_layers_texture.width) * float(m_object_max_z)));
     shader->set_uniform("z_texture_row_to_normalized", 1.0f / float(m_layers_texture.height));
     shader->set_uniform("z_cursor", float(m_object_max_z) * float(this->get_cursor_z_relative(canvas)));
     shader->set_uniform("z_cursor_band_width", float(this->band_width));
 
-        // Initialize the layer height texture mapping.
-        GLsizei w = (GLsizei)m_layers_texture.width;
-        GLsizei h = (GLsizei)m_layers_texture.height;
-        GLsizei half_w = w / 2;
-        GLsizei half_h = h / 2;
-        glsafe(::glPixelStorei(GL_UNPACK_ALIGNMENT, 1));
-        glsafe(::glBindTexture(GL_TEXTURE_2D, m_z_texture_id));
-        glsafe(::glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0));
-        glsafe(::glTexImage2D(GL_TEXTURE_2D, 1, GL_RGBA, half_w, half_h, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0));
-        glsafe(::glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, m_layers_texture.data.data()));
-        glsafe(::glTexSubImage2D(GL_TEXTURE_2D, 1, 0, 0, half_w, half_h, GL_RGBA, GL_UNSIGNED_BYTE, m_layers_texture.data.data() + m_layers_texture.width * m_layers_texture.height * 4));
-        for (const GLVolume* glvolume : volumes.volumes) {
-            // Render the object using the layer editing shader and texture.
-            if (! glvolume->is_active || glvolume->composite_id.object_id != this->last_object_id || glvolume->is_modifier)
-                continue;
+    // Initialize the layer height texture mapping.
+    GLsizei w = (GLsizei)m_layers_texture.width;
+    GLsizei h = (GLsizei)m_layers_texture.height;
+    GLsizei half_w = w / 2;
+    GLsizei half_h = h / 2;
+    glsafe(::glPixelStorei(GL_UNPACK_ALIGNMENT, 1));
+    glsafe(::glBindTexture(GL_TEXTURE_2D, m_z_texture_id));
+    glsafe(::glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0));
+    glsafe(::glTexImage2D(GL_TEXTURE_2D, 1, GL_RGBA, half_w, half_h, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0));
+    glsafe(::glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, m_layers_texture.data.data()));
+    glsafe(::glTexSubImage2D(GL_TEXTURE_2D, 1, 0, 0, half_w, half_h, GL_RGBA, GL_UNSIGNED_BYTE, m_layers_texture.data.data() + m_layers_texture.width * m_layers_texture.height * 4));
+    for (const GLVolume* glvolume : volumes.volumes) {
+        // Render the object using the layer editing shader and texture.
+        if (! glvolume->is_active || glvolume->composite_id.object_id != this->last_object_id || glvolume->is_modifier)
+            continue;
 
-        shader->set_uniform("volume_world_matrix", glvolume->world_matrix());
-        shader->set_uniform("object_max_z", GLfloat(0));
-            glvolume->render();
-        }
-        // Revert back to the previous shader.
-        glBindTexture(GL_TEXTURE_2D, 0);
+    shader->set_uniform("volume_world_matrix", glvolume->world_matrix());
+    shader->set_uniform("object_max_z", GLfloat(0));
+        glvolume->render();
+    }
+    // Revert back to the previous shader.
+    glBindTexture(GL_TEXTURE_2D, 0);
     if (current_shader != nullptr)
         current_shader->start_using();
 }
@@ -1527,10 +1527,12 @@ bool GLCanvas3D::is_layers_editing_allowed() const
 
 void GLCanvas3D::reset_layer_height_profile()
 {
-    wxGetApp().plater()->take_snapshot(_L("Variable layer height - Reset"));
-    m_layers_editing.reset_layer_height_profile(*this);
-    m_layers_editing.state = LayersEditing::Completed;
-    m_dirty = true;
+    if (is_layers_editing_enabled()) {
+        wxGetApp().plater()->take_snapshot(_L("Variable layer height - Reset"));
+        m_layers_editing.reset_layer_height_profile(*this);
+        m_layers_editing.state = LayersEditing::Completed;
+        m_dirty = true;
+    }
 }
 
 void GLCanvas3D::adaptive_layer_height_profile(float quality_factor)

src/slic3r/GUI/GUI_ObjectList.cpp

@@ -3401,14 +3401,14 @@ void ObjectList::del_layer_range(const t_layer_height_range& range)
 static double get_min_layer_height(const int extruder_idx)
 {
     const DynamicPrintConfig& config = wxGetApp().preset_bundle->printers.get_edited_preset().config;
-    return config.opt_float("min_layer_height", std::max(0, extruder_idx - 1));
+    return config.get_computed_value("min_layer_height", std::max(0, extruder_idx - 1));
 }
 
 static double get_max_layer_height(const int extruder_idx)
 {
     const DynamicPrintConfig& config = wxGetApp().preset_bundle->printers.get_edited_preset().config;
     int extruder_idx_zero_based = std::max(0, extruder_idx - 1);
-    double max_layer_height = config.opt_float("max_layer_height", extruder_idx_zero_based);
+    double max_layer_height = config.get_computed_value("max_layer_height", extruder_idx_zero_based);
 
     // In case max_layer_height is set to zero, it should default to 75 % of nozzle diameter:
     if (max_layer_height < EPSILON)

src/slic3r/GUI/PresetHints.cpp

@@ -496,7 +496,7 @@ std::string PresetHints::top_bottom_shell_thickness_explanation(const PresetBund
     double  layer_height                    = print_config.opt_float("layer_height");
     bool    variable_layer_height			= printer_config.opt_bool("variable_layer_height");
     //FIXME the following line takes into account the 1st extruder only.
-    double  min_layer_height				= variable_layer_height ? Slicing::min_layer_height_from_nozzle(printer_config, 1) : layer_height;
+    double  min_layer_height				= variable_layer_height ? Slicing::min_layer_height_from_nozzle(printer_config, 0) : layer_height;
 
 	if (layer_height <= 0.f) {
 		out += _utf8(L("Top / bottom shell thickness hint: Not available due to invalid layer height."));

src/slic3r/GUI/Tab.cpp

@@ -1191,6 +1191,11 @@ void Tab::on_value_change(const std::string& opt_key, const boost::any& value)
         wxGetApp().mainframe->plater()->canvas3D()->set_arrange_settings(m_presets->get_edited_preset().config, m_presets->get_edited_preset().printer_technology());
     }
 
+    // reset variable layer height if min/max has changed, as it's probably now invalid.
+    if (opt_key.find("min_layer_height") == 0   || opt_key.find("max_layer_height") == 0) {
+        wxPostEvent((wxEvtHandler*)wxGetApp().mainframe->plater()->canvas3D()->get_wxglcanvas(), SimpleEvent(EVT_GLCANVAS_RESET_LAYER_HEIGHT_PROFILE));
+    }
+
     //wxGetApp().preset_bundle->value_changed(opt_key);
     // update phony fields
     
@@ -3036,24 +3041,26 @@ void TabPrinter::toggle_options()
         int64_t z_step_Mlong = (int64_t)(z_step * 1000000.);
         DynamicPrintConfig new_conf;
         bool has_changed = false;
-        const std::vector<double>& min_layer_height = m_config->option<ConfigOptionFloats>("min_layer_height")->values;
-        for (int i = 0; i < min_layer_height.size(); i++) {
-            if (min_layer_height[i] != 0 && (int64_t)(min_layer_height[i] * 1000000.) % z_step_Mlong != 0) {
-                if (!has_changed)
-                    new_conf = *m_config;
-                new_conf.option<ConfigOptionFloats>("min_layer_height")->values[i] = std::max(z_step, Slic3r::check_z_step(new_conf.option<ConfigOptionFloats>("min_layer_height")->values[i], z_step));
-                has_changed = true;
-            }
-        }
         const std::vector<double>& nozzle_diameters = m_config->option<ConfigOptionFloats>("nozzle_diameter")->values;
-        std::vector<double> max_layer_height = m_config->option<ConfigOptionFloats>("max_layer_height")->values;
+        const std::vector<FloatOrPercent>& min_layer_height = m_config->option<ConfigOptionFloatsOrPercents>("min_layer_height")->values;
+        for (int i = 0; i < min_layer_height.size(); i++) {
+            if(!min_layer_height[i].percent)
+                if (min_layer_height[i].get_abs_value(nozzle_diameters[i]) != 0 && (int64_t)(min_layer_height[i].get_abs_value(nozzle_diameters[i]) * 1000000.) % z_step_Mlong != 0) {
+                    if (!has_changed)
+                        new_conf = *m_config;
+                    new_conf.option<ConfigOptionFloatsOrPercents>("min_layer_height")->values[i] = FloatOrPercent{ std::max(z_step, Slic3r::check_z_step(min_layer_height[i].get_abs_value(nozzle_diameters[i]), z_step)), false };
+                    has_changed = true;
+                }
+        }
+        std::vector<FloatOrPercent> max_layer_height = m_config->option<ConfigOptionFloatsOrPercents>("max_layer_height")->values;
         for (int i = 0; i < max_layer_height.size(); i++) {
-            if ((int64_t)(max_layer_height[i] * 1000000.) % z_step_Mlong != 0) {
-                if (!has_changed)
-                    new_conf = *m_config;
-                new_conf.option<ConfigOptionFloats>("max_layer_height")->values[i] = std::max(z_step, Slic3r::check_z_step(new_conf.option<ConfigOptionFloats>("max_layer_height")->values[i], z_step));
-                has_changed = true;
-            }
+            if (!max_layer_height[i].percent)
+                if ((int64_t)(max_layer_height[i].get_abs_value(nozzle_diameters[i]) * 1000000.) % z_step_Mlong != 0) {
+                    if (!has_changed)
+                        new_conf = *m_config;
+                    new_conf.option<ConfigOptionFloatsOrPercents>("max_layer_height")->values[i] = FloatOrPercent{ std::max(z_step, Slic3r::check_z_step(new_conf.option<ConfigOptionFloats>("max_layer_height")->values[i], z_step)), false };
+                    has_changed = true;
+                }
         }
         if (has_changed) {
             load_config(new_conf);