diff --git a/src/libslic3r/Config.cpp b/src/libslic3r/Config.cpp
index 09b48f69ba..346665a135 100644
--- a/src/libslic3r/Config.cpp
+++ b/src/libslic3r/Config.cpp
@@ -653,22 +653,52 @@ double ConfigBase::get_abs_value(const t_config_option_key &opt_key) const
 {
     // Get stored option value.
     const ConfigOption *raw_opt = this->option(opt_key);
+    if (raw_opt == nullptr) {
+      std::stringstream ss;
+      ss << "You can't define an option that need " << opt_key << " without defining it!";
+      throw std::runtime_error(ss.str());
+    }
     assert(raw_opt != nullptr);
+
     if (raw_opt->type() == coFloat)
         return static_cast<const ConfigOptionFloat*>(raw_opt)->value;
+    if (raw_opt->type() == coInt)
+      return static_cast<const ConfigOptionInt *>(raw_opt)->value;
+    if (raw_opt->type() == coBool)
+      return static_cast<const ConfigOptionBool *>(raw_opt)->value ? 1 : 0;
+
+    const ConfigOptionPercent *cast_opt = nullptr;
     if (raw_opt->type() == coFloatOrPercent) {
-        // Get option definition.
-        const ConfigDef *def = this->def();
-        if (def == nullptr)
-            throw NoDefinitionException(opt_key);
-        const ConfigOptionDef *opt_def = def->get(opt_key);
-        assert(opt_def != nullptr);
-        // Compute absolute value over the absolute value of the base option.
-        //FIXME there are some ratio_over chains, which end with empty ratio_with.
-        // For example, XXX_extrusion_width parameters are not handled by get_abs_value correctly.
-        return opt_def->ratio_over.empty() ? 0. :
-            static_cast<const ConfigOptionFloatOrPercent*>(raw_opt)->get_abs_value(this->get_abs_value(opt_def->ratio_over));
+        auto cofop = static_cast<const ConfigOptionFloatOrPercent*>(raw_opt);
+            if (cofop->value == 0 && boost::ends_with(opt_key, "_line_width")) {
+                return this->get_abs_value("line_width");
+            }
+            if (!cofop->percent)
+                return cofop->value;
+            cast_opt = cofop;
     }
+
+    if (raw_opt->type() == coPercent) {
+      cast_opt = static_cast<const ConfigOptionPercent *>(raw_opt);
+    }
+
+    // Get option definition.
+    const ConfigDef *def = this->def();
+    if (def == nullptr)
+        throw NoDefinitionException(opt_key);
+    const ConfigOptionDef *opt_def = def->get(opt_key);
+
+
+    assert(opt_def != nullptr);
+    if (opt_def->ratio_over == "")
+        return cast_opt->get_abs_value(1);
+    // Compute absolute value over the absolute value of the base option.
+    //FIXME there are some ratio_over chains, which end with empty ratio_with.
+    // For example, XXX_extrusion_width parameters are not handled by get_abs_value correctly.
+    return opt_def->ratio_over.empty() ? 0. :
+        static_cast<const ConfigOptionFloatOrPercent*>(raw_opt)->get_abs_value(this->get_abs_value(opt_def->ratio_over));
+    
+
     throw ConfigurationError("ConfigBase::get_abs_value(): Not a valid option type for get_abs_value()");
 }
 
diff --git a/src/libslic3r/Fill/FillAdaptive.cpp b/src/libslic3r/Fill/FillAdaptive.cpp
index 692b5cec77..bc1b24a81d 100644
--- a/src/libslic3r/Fill/FillAdaptive.cpp
+++ b/src/libslic3r/Fill/FillAdaptive.cpp
@@ -301,7 +301,7 @@ std::pair<double, double> adaptive_fill_line_spacing(const PrintObject &print_ob
         bool                     nonempty               = config.sparse_infill_density > 0;
         bool                     has_adaptive_infill    = nonempty && config.sparse_infill_pattern == ipAdaptiveCubic;
         bool                     has_support_infill     = nonempty && config.sparse_infill_pattern == ipSupportCubic;
-        double                   sparse_infill_line_width = config.sparse_infill_line_width;
+        double                   sparse_infill_line_width = config.sparse_infill_line_width.get_abs_value(max_nozzle_diameter);
         region_fill_data.push_back(RegionFillData({
             has_adaptive_infill ? Tristate::Maybe : Tristate::No,
             has_support_infill ? Tristate::Maybe : Tristate::No,
diff --git a/src/libslic3r/Fill/Lightning/Generator.cpp b/src/libslic3r/Fill/Lightning/Generator.cpp
index fb00cbe6e2..6b453ca8ef 100644
--- a/src/libslic3r/Fill/Lightning/Generator.cpp
+++ b/src/libslic3r/Fill/Lightning/Generator.cpp
@@ -75,9 +75,7 @@ Generator::Generator(const PrintObject &print_object, const std::function<void()
     // Note: There's not going to be a layer below the first one, so the 'initial layer height' doesn't have to be taken into account.
     const double               layer_thickness      = scaled<double>(object_config.layer_height.value);
 
-    //m_infill_extrusion_width = scaled<float>(region_config.infill_extrusion_width.percent ? default_infill_extrusion_width * 0.01 * region_config.infill_extrusion_width : region_config.infill_extrusion_width);
-    //m_supporting_radius      = coord_t(m_infill_extrusion_width) * 100 / coord_t(region_config.fill_density.value);
-    m_infill_extrusion_width = scaled<float>(region_config.sparse_infill_line_width.value);
+    m_infill_extrusion_width = scaled<float>(region_config.sparse_infill_line_width.get_abs_value(max_nozzle_diameter));
     m_supporting_radius = coord_t(m_infill_extrusion_width) * 100 / region_config.sparse_infill_density;
 
     const double lightning_infill_overhang_angle      = M_PI / 4; // 45 degrees
@@ -103,7 +101,7 @@ Generator::Generator(PrintObject* m_object, std::vector<Polygons>& contours, std
     // Note: There's not going to be a layer below the first one, so the 'initial layer height' doesn't have to be taken into account.
     const double               layer_thickness      = scaled<double>(object_config.layer_height.value);
 
-    m_infill_extrusion_width = scaled<float>(region_config.sparse_infill_line_width.value);
+    m_infill_extrusion_width = scaled<float>(region_config.sparse_infill_line_width.get_abs_value(max_nozzle_diameter));
     //m_supporting_radius: against to the density of lightning, failures may happen if set to high density
     //higher density lightning makes support harder, more time-consuming on computing and printing, but more reliable on supporting overhangs
     //lower density lightning performs opposite
diff --git a/src/libslic3r/Flow.cpp b/src/libslic3r/Flow.cpp
index 0fbefb7240..24a324fd5e 100644
--- a/src/libslic3r/Flow.cpp
+++ b/src/libslic3r/Flow.cpp
@@ -67,8 +67,6 @@ double Flow::extrusion_width(const std::string& opt_key, const ConfigOptionFloat
 {
 	assert(opt != nullptr);
 
-	bool first_layer = boost::starts_with(opt_key, "initial_layer_");
-
 #if 0
 // This is the logic used for skit / brim, but not for the rest of the 1st layer.
 	if (opt->value == 0. && first_layer) {
@@ -84,24 +82,18 @@ double Flow::extrusion_width(const std::string& opt_key, const ConfigOptionFloat
 		opt = config.option<ConfigOptionFloatOrPercent>("line_width");
 		if (opt == nullptr)
     		throw_on_missing_variable(opt_key, "line_width");
-    	// Use the "layer_height" instead of "initial_layer_print_height".
-    	first_layer = false;
 	}
 
-	if (opt->percent) {
-		auto opt_key_layer_height = first_layer ? "initial_layer_print_height" : "layer_height";
-        auto opt_layer_height = config.option(opt_key_layer_height);
-    	if (opt_layer_height == nullptr)
-    		throw_on_missing_variable(opt_key, opt_key_layer_height);
-        assert(! first_layer || ! static_cast<const ConfigOptionFloatOrPercent*>(opt_layer_height)->percent);
-		return opt->get_abs_value(opt_layer_height->getFloat());
+    auto opt_nozzle_diameters = config.option<ConfigOptionFloats>("nozzle_diameter");
+    if (opt_nozzle_diameters == nullptr)
+        throw_on_missing_variable(opt_key, "nozzle_diameter");
+
+    if (opt->percent) {
+		return opt->get_abs_value(float(opt_nozzle_diameters->get_at(first_printing_extruder)));
 	}
 
 	if (opt->value == 0.) {
         // If user left option to 0, calculate a sane default width.
-    	auto opt_nozzle_diameters = config.option<ConfigOptionFloats>("nozzle_diameter");
-    	if (opt_nozzle_diameters == nullptr)
-    		throw_on_missing_variable(opt_key, "nozzle_diameter");
         return auto_extrusion_width(opt_key_to_flow_role(opt_key), float(opt_nozzle_diameters->get_at(first_printing_extruder)));
     }
 
@@ -116,18 +108,18 @@ double Flow::extrusion_width(const std::string& opt_key, const ConfigOptionResol
 
 // This constructor builds a Flow object from an extrusion width config setting
 // and other context properties.
-Flow Flow::new_from_config_width(FlowRole role, const ConfigOptionFloat &width, float nozzle_diameter, float height)
+Flow Flow::new_from_config_width(FlowRole role, const ConfigOptionFloatOrPercent &width, float nozzle_diameter, float height)
 {
     if (height <= 0)
         throw Slic3r::InvalidArgument("Invalid flow height supplied to new_from_config_width()");
 
     float w;
-    if (width.value == 0.) {
+    if (!width.percent  && width.value <= 0.) {
         // If user left option to 0, calculate a sane default width.
         w = auto_extrusion_width(role, nozzle_diameter);
     } else {
         // If user set a manual value, use it.
-        w = float(width.value);
+      w = float(width.get_abs_value(nozzle_diameter));
     }
     
     return Flow(w, height, rounded_rectangle_extrusion_spacing(w, height), nozzle_diameter, false);
diff --git a/src/libslic3r/Flow.hpp b/src/libslic3r/Flow.hpp
index 7ead899a19..c7954158f5 100644
--- a/src/libslic3r/Flow.hpp
+++ b/src/libslic3r/Flow.hpp
@@ -98,7 +98,7 @@ public:
 
     static Flow bridging_flow(float dmr, float nozzle_diameter) { return Flow { dmr, dmr, bridge_extrusion_spacing(dmr), nozzle_diameter, true }; }
 
-    static Flow new_from_config_width(FlowRole role, const ConfigOptionFloat &width, float nozzle_diameter, float height);
+    static Flow new_from_config_width(FlowRole role, const ConfigOptionFloatOrPercent &width, float nozzle_diameter, float height);
 
     // Spacing of extrusions with rounded extrusion model.
     static float rounded_rectangle_extrusion_spacing(float width, float height);
diff --git a/src/libslic3r/GCode.cpp b/src/libslic3r/GCode.cpp
index 3b856f6a5a..eea1dd9ccc 100644
--- a/src/libslic3r/GCode.cpp
+++ b/src/libslic3r/GCode.cpp
@@ -1783,11 +1783,13 @@ void GCode::_do_export(Print& print, GCodeOutputStream &file, ThumbnailsGenerato
 
         //BBS: calculate the volumetric speed of outer wall. Ignore pre-object setting and multi-filament, and just use the default setting
         {
+
             float filament_max_volumetric_speed = m_config.option<ConfigOptionFloats>("filament_max_volumetric_speed")->get_at(initial_non_support_extruder_id);
-            float outer_wall_line_width = print.default_region_config().outer_wall_line_width.value;
+            const double nozzle_diameter = m_config.nozzle_diameter.get_at(initial_non_support_extruder_id);
+            float outer_wall_line_width = this->config().get_abs_value("outer_wall_line_width", nozzle_diameter);
             if (outer_wall_line_width == 0.0) {
-                float default_line_width = print.default_object_config().line_width.value;
-                outer_wall_line_width = default_line_width == 0.0 ? m_config.nozzle_diameter.get_at(initial_non_support_extruder_id) : default_line_width;
+                float default_line_width =  this->config().get_abs_value("line_width", nozzle_diameter);
+                outer_wall_line_width = default_line_width == 0.0 ? nozzle_diameter : default_line_width;
             }
             Flow outer_wall_flow = Flow(outer_wall_line_width, m_config.layer_height, m_config.nozzle_diameter.get_at(initial_non_support_extruder_id));
             float outer_wall_speed = print.default_region_config().outer_wall_speed.value;
diff --git a/src/libslic3r/GCode/ToolOrdering.cpp b/src/libslic3r/GCode/ToolOrdering.cpp
index 4d474d7133..77e5db3365 100644
--- a/src/libslic3r/GCode/ToolOrdering.cpp
+++ b/src/libslic3r/GCode/ToolOrdering.cpp
@@ -239,7 +239,10 @@ std::vector<unsigned int> ToolOrdering::generate_first_layer_tool_order(const Pr
             int extruder_id = layerm->region().config().option("wall_filament")->getInt();
             
             for (auto expoly : layerm->raw_slices) {
-                if (offset_ex(expoly, -0.2 * scale_(print.config().initial_layer_line_width)).empty())
+                const double nozzle_diameter = print.config().nozzle_diameter.get_at(0);
+                const coordf_t initial_layer_line_width = print.config().get_abs_value("initial_layer_line_width", nozzle_diameter);
+
+                if (offset_ex(expoly, -0.2 * scale_(initial_layer_line_width)).empty())
                     continue;
 
                 double contour_area = expoly.contour.area();
@@ -279,7 +282,10 @@ std::vector<unsigned int> ToolOrdering::generate_first_layer_tool_order(const Pr
     for (auto layerm : first_layer->regions()) {
         int extruder_id = layerm->region().config().option("wall_filament")->getInt();
         for (auto expoly : layerm->raw_slices) {
-            if (offset_ex(expoly, -0.2 * scale_(object.config().line_width)).empty())
+            const double nozzle_diameter = object.print()->config().nozzle_diameter.get_at(0);
+            const coordf_t line_width = object.config().get_abs_value("line_width", nozzle_diameter);
+
+            if (offset_ex(expoly, -0.2 * scale_(line_width)).empty())
                 continue;
 
             double contour_area = expoly.contour.area();
diff --git a/src/libslic3r/Layer.cpp b/src/libslic3r/Layer.cpp
index 5191c22939..6a0cf9cfbf 100644
--- a/src/libslic3r/Layer.cpp
+++ b/src/libslic3r/Layer.cpp
@@ -175,6 +175,7 @@ void Layer::make_perimeters()
                         && config.filter_out_gap_fill.value == other_config.filter_out_gap_fill.value
 		                && config.detect_overhang_wall                   == other_config.detect_overhang_wall
 		                && config.opt_serialize("inner_wall_line_width") == other_config.opt_serialize("inner_wall_line_width")
+		                && config.opt_serialize("outer_wall_line_width") == other_config.opt_serialize("outer_wall_line_width")
 		                && config.detect_thin_wall                  == other_config.detect_thin_wall
 		                //&& config.wall_infill_order   == other_config.wall_infill_order
 		                && config.infill_wall_overlap              == other_config.infill_wall_overlap
diff --git a/src/libslic3r/MultiMaterialSegmentation.cpp b/src/libslic3r/MultiMaterialSegmentation.cpp
index 06efb5fdd5..4efedc1ccb 100644
--- a/src/libslic3r/MultiMaterialSegmentation.cpp
+++ b/src/libslic3r/MultiMaterialSegmentation.cpp
@@ -1545,7 +1545,7 @@ static inline std::vector<std::vector<ExPolygons>> mmu_segmentation_top_and_bott
         //BBS: spacing according to width and layer height
         float   extrusion_spacing{ 0.f };
     };
-    auto layer_color_stat = [&layers = std::as_const(layers)](const size_t layer_idx, const size_t color_idx) -> LayerColorStat {
+    auto layer_color_stat = [&layers = std::as_const(layers), &print_object](const size_t layer_idx, const size_t color_idx) -> LayerColorStat {
         LayerColorStat out;
         const Layer &layer = *layers[layer_idx];
         for (const LayerRegion *region : layer.regions())
@@ -1554,16 +1554,18 @@ static inline std::vector<std::vector<ExPolygons>> mmu_segmentation_top_and_bott
                 // As this region may split existing regions, we collect statistics over all regions for color_idx == 0.
                 color_idx == 0 || config.wall_filament == int(color_idx)) {
                 //BBS: the extrusion line width is outer wall rather than inner wall
-                out.extrusion_width     = std::max<float>(out.extrusion_width, float(config.outer_wall_line_width));
+                const double nozzle_diameter = print_object.print()->config().nozzle_diameter.get_at(0);
+                double outer_wall_line_width = config.get_abs_value("outer_wall_line_width", nozzle_diameter);
+                out.extrusion_width     = std::max<float>(out.extrusion_width, outer_wall_line_width);
                 out.top_shell_layers    = std::max<int>(out.top_shell_layers, config.top_shell_layers);
                 out.bottom_shell_layers = std::max<int>(out.bottom_shell_layers, config.bottom_shell_layers);
                 out.small_region_threshold = config.gap_infill_speed.value > 0 ?
                                              // Gap fill enabled. Enable a single line of 1/2 extrusion width.
-                                             0.5f * float(config.outer_wall_line_width) :
+                                             0.5f * outer_wall_line_width :
                                              // Gap fill disabled. Enable two lines slightly overlapping.
-                                             float(config.outer_wall_line_width) + 0.7f * Flow::rounded_rectangle_extrusion_spacing(float(config.outer_wall_line_width), float(layer.height));
+                                             outer_wall_line_width + 0.7f * Flow::rounded_rectangle_extrusion_spacing(outer_wall_line_width, float(layer.height));
                 out.small_region_threshold = scaled<float>(out.small_region_threshold * 0.5f);
-                out.extrusion_spacing = Flow::rounded_rectangle_extrusion_spacing(float(config.outer_wall_line_width), float(layer.height));
+                out.extrusion_spacing = Flow::rounded_rectangle_extrusion_spacing(float(outer_wall_line_width), float(layer.height));
                 ++ out.num_regions;
             }
         assert(out.num_regions > 0);
diff --git a/src/libslic3r/PerimeterGenerator.cpp b/src/libslic3r/PerimeterGenerator.cpp
index bf04e29c39..0c4ed1aef4 100644
--- a/src/libslic3r/PerimeterGenerator.cpp
+++ b/src/libslic3r/PerimeterGenerator.cpp
@@ -1019,15 +1019,13 @@ void PerimeterGenerator::process_classic()
                     // get the real top surface
                     ExPolygons grown_lower_slices;
                     ExPolygons bridge_checker;
-                    // BBS: check whether surface be bridge or not
+                    auto nozzle_diameter = this->print_config->nozzle_diameter.get_at(this->config->wall_filament - 1);
+                    // Check whether surface be bridge or not
                     if (this->lower_slices != NULL) {
                         // BBS: get the Polygons below the polygon this layer
                         Polygons lower_polygons_series_clipped = ClipperUtils::clip_clipper_polygons_with_subject_bbox(*this->lower_slices, last_box);
-
                         double bridge_offset = std::max(double(ext_perimeter_spacing), (double(perimeter_width)));
                         // SoftFever: improve bridging
-                        auto nozzle_diameter =
-                            this->print_config->nozzle_diameter.get_at(this->config->wall_filament - 1);
                         const float bridge_margin =
                             std::min(float(scale_(BRIDGE_INFILL_MARGIN)),
                                      float(scale_(nozzle_diameter * BRIDGE_INFILL_MARGIN / 0.4)));
@@ -1047,7 +1045,8 @@ void PerimeterGenerator::process_classic()
                     // increase by half peri the inner space to fill the frontier between last and stored.
                     top_fills = union_ex(top_fills, top_polygons);
                     //set the clip to the external wall but go back inside by infill_extrusion_width/2 to be sure the extrusion won't go outside even with a 100% overlap.
-                    double infill_spacing_unscaled = this->config->sparse_infill_line_width.value;
+                    double infill_spacing_unscaled = this->config->sparse_infill_line_width.get_abs_value(nozzle_diameter);
+                    if (infill_spacing_unscaled == 0) infill_spacing_unscaled = Flow::auto_extrusion_width(frInfill, nozzle_diameter);
                     fill_clip = offset_ex(last, double(ext_perimeter_spacing / 2) - scale_(infill_spacing_unscaled / 2));
                     //ExPolygons oldLast = last;
 
diff --git a/src/libslic3r/Print.cpp b/src/libslic3r/Print.cpp
index 4cd8484994..05b42ec7cc 100644
--- a/src/libslic3r/Print.cpp
+++ b/src/libslic3r/Print.cpp
@@ -1099,13 +1099,9 @@ StringObjectException Print::validate(StringObjectException *warning, Polygons*
                 return ("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 {
-            // This may change in the future, if we switch to "extrusion width wrt. nozzle diameter"
-            // instead of currently used logic "extrusion width wrt. layer height", see GH issues #1923 #2829.
-//        	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);
-            double extrusion_width_min = config.get_abs_value(opt_key);
-            double extrusion_width_max = config.get_abs_value(opt_key);
+        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 == 0) {
         		// Default "auto-generated" extrusion width is always valid.
         	} else if (extrusion_width_min <= layer_height) {
@@ -1297,10 +1293,10 @@ double Print::skirt_first_layer_height() const
 
 Flow Print::brim_flow() const
 {
-    ConfigOptionFloat width = m_config.initial_layer_line_width;
-    if (width.value == 0)
+    ConfigOptionFloatOrPercent width = m_config.initial_layer_line_width;
+    if (width.value <= 0)
         width = m_print_regions.front()->config().inner_wall_line_width;
-    if (width.value == 0)
+    if (width.value <= 0)
         width = m_objects.front()->config().line_width;
 
     /* We currently use a random region's perimeter extruder.
@@ -1310,6 +1306,7 @@ Flow Print::brim_flow() const
        generation as well. */
     return Flow::new_from_config_width(
         frPerimeter,
+        // Flow::new_from_config_width takes care of the percent to value substitution
 		width,
         (float)m_config.nozzle_diameter.get_at(m_print_regions.front()->config().wall_filament-1),
 		(float)this->skirt_first_layer_height());
@@ -1317,8 +1314,8 @@ Flow Print::brim_flow() const
 
 Flow Print::skirt_flow() const
 {
-    ConfigOptionFloat width = m_config.initial_layer_line_width;
-    if (width.value == 0)
+    ConfigOptionFloatOrPercent width = m_config.initial_layer_line_width;
+    if (width.value <= 0)
         width = m_objects.front()->config().line_width;
 
     /* We currently use a random object's support material extruder.
@@ -1328,6 +1325,7 @@ Flow Print::skirt_flow() const
        generation as well. */
     return Flow::new_from_config_width(
         frPerimeter,
+        // Flow::new_from_config_width takes care of the percent to value substitution
 		width,
 		(float)m_config.nozzle_diameter.get_at(m_objects.front()->config().support_filament-1),
 		(float)this->skirt_first_layer_height());
diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index 6e4332a5e9..60cd78e1ce 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -1057,14 +1057,17 @@ void PrintConfigDef::init_fff_params()
     def->enum_labels = def_top_fill_pattern->enum_labels;
     def->set_default_value(new ConfigOptionEnum<InfillPattern>(ipRectilinear));
 
-    def = this->add("outer_wall_line_width", coFloat);
+    def = this->add("outer_wall_line_width", coFloatOrPercent);
     def->label = L("Outer wall");
     def->category = L("Quality");
-    def->tooltip = L("Line width of outer wall");
-    def->sidetext = L("mm");
+    def->tooltip = L("Line width of outer wall. If expressed as a %, it will be computed over the nozzle diameter.");
+    def->sidetext = L("mm or %");
+    def->ratio_over = "nozzle_diameter";
     def->min = 0;
+    def->max = 1000;
+    def->max_literal = 10;
     def->mode = comAdvanced;
-    def->set_default_value(new ConfigOptionFloat(0));
+    def->set_default_value(new ConfigOptionFloatOrPercent(0., false));
 
     def = this->add("outer_wall_speed", coFloat);
     def->label = L("Outer wall");
@@ -1208,15 +1211,17 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloats { 0.02 });
 
-    def = this->add("line_width", coFloat);
+    def = this->add("line_width", coFloatOrPercent);
     def->label = L("Default");
     def->category = L("Quality");
-    def->tooltip = L("Default line width if some line width is set to be zero");
-    def->sidetext = L("mm");
+    def->tooltip = L("Default line width if other line widths are set to 0. If expressed as a %, it will be computed over the nozzle diameter.");
+    def->sidetext = L("mm or %");
+    def->ratio_over = "nozzle_diameter";
     def->min = 0;
-    def->max = 10;
+    def->max = 1000;
+    def->max_literal = 10;
     def->mode = comAdvanced;
-    def->set_default_value(new ConfigOptionFloat(0.4));
+    def->set_default_value(new ConfigOptionFloatOrPercent(0, false));
 
     def = this->add("reduce_fan_stop_start_freq", coBools);
     def->label = L("Keep fan always on");
@@ -1637,14 +1642,18 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloat(12));
 
-    def = this->add("initial_layer_line_width", coFloat);
+    def = this->add("initial_layer_line_width", coFloatOrPercent);
     def->label = L("Initial layer");
     def->category = L("Quality");
-    def->tooltip = L("Line width of initial layer");
-    def->sidetext = L("mm");
+    def->tooltip = L("Line width of initial layer. If expressed as a %, it will be computed over the nozzle diameter.");
+    def->sidetext = L("mm or %");
+    def->ratio_over = "nozzle_diameter";
     def->min = 0;
+    def->max = 1000;
+    def->max_literal = 10;
     def->mode = comAdvanced;
-    def->set_default_value(new ConfigOptionFloat(0.4));
+    def->set_default_value(new ConfigOptionFloatOrPercent(0., false));
+
 
     def = this->add("initial_layer_print_height", coFloat);
     def->label = L("Initial layer height");
@@ -1942,14 +1951,17 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionInt(1));
 
-    def = this->add("sparse_infill_line_width", coFloat);
+    def = this->add("sparse_infill_line_width", coFloatOrPercent);
     def->label = L("Sparse infill");
     def->category = L("Quality");
-    def->tooltip = L("Line width of internal sparse infill");
-    def->sidetext = L("mm");
+    def->tooltip = L("Line width of internal sparse infill. If expressed as a %, it will be computed over the nozzle diameter.");
+    def->sidetext = L("mm or %");
+    def->ratio_over = "nozzle_diameter";
     def->min = 0;
+    def->max = 1000;
+    def->max_literal = 10;
     def->mode = comAdvanced;
-    def->set_default_value(new ConfigOptionFloat(0.4));
+    def->set_default_value(new ConfigOptionFloatOrPercent(0., false));
 
     def = this->add("infill_wall_overlap", coPercent);
     def->label = L("Infill/Wall overlap");
@@ -2374,14 +2386,17 @@ void PrintConfigDef::init_fff_params()
     def->mode = comDevelop;
     def->set_default_value(new ConfigOptionInt(1));
 
-    def = this->add("inner_wall_line_width", coFloat);
+    def = this->add("inner_wall_line_width", coFloatOrPercent);
     def->label = L("Inner wall");
     def->category = L("Quality");
-    def->tooltip = L("Line width of inner wall");
-    def->sidetext = L("mm");
+    def->tooltip = L("Line width of inner wall. If expressed as a %, it will be computed over the nozzle diameter.");
+    def->sidetext = L("mm or %");
+    def->ratio_over = "nozzle_diameter";
     def->min = 0;
+    def->max = 1000;
+    def->max_literal = 10;
     def->mode = comAdvanced;
-    def->set_default_value(new ConfigOptionFloat(0.4));
+    def->set_default_value(new ConfigOptionFloatOrPercent(0., false));
 
     def = this->add("inner_wall_speed", coFloat);
     def->label = L("Inner wall");
@@ -2773,14 +2788,17 @@ void PrintConfigDef::init_fff_params()
     def->mode = comDevelop;
     def->set_default_value(new ConfigOptionInt(1));
 
-    def = this->add("internal_solid_infill_line_width", coFloat);
+    def = this->add("internal_solid_infill_line_width", coFloatOrPercent);
     def->label = L("Internal solid infill");
     def->category = L("Quality");
-    def->tooltip = L("Line width of internal solid infill");
-    def->sidetext = L("mm");
+    def->tooltip = L("Line width of internal solid infill. If expressed as a %, it will be computed over the nozzle diameter.");
+    def->sidetext = L("mm or %");
+    def->ratio_over = "nozzle_diameter";
     def->min = 0;
+    def->max = 1000;
+    def->max_literal = 10;
     def->mode = comAdvanced;
-    def->set_default_value(new ConfigOptionFloat(0.4));
+    def->set_default_value(new ConfigOptionFloatOrPercent(0., false));
 
     def = this->add("internal_solid_infill_speed", coFloat);
     def->label = L("Internal solid infill");
@@ -2995,14 +3013,17 @@ void PrintConfigDef::init_fff_params()
     def->mode = comSimple;
     def->set_default_value(new ConfigOptionInt(1));
 
-    def = this->add("support_line_width", coFloat);
+    def = this->add("support_line_width", coFloatOrPercent);
     def->label = L("Support");
     def->category = L("Quality");
-    def->tooltip = L("Line width of support");
-    def->sidetext = L("mm");
+    def->tooltip = L("Line width of support. If expressed as a %, it will be computed over the nozzle diameter.");
+    def->sidetext = L("mm or %");
+    def->ratio_over = "nozzle_diameter";
     def->min = 0;
+    def->max = 1000;
+    def->max_literal = 10;
     def->mode = comAdvanced;
-    def->set_default_value(new ConfigOptionFloat(0.4));
+    def->set_default_value(new ConfigOptionFloatOrPercent(0., false));
 
     def = this->add("support_interface_loop_pattern", coBool);
     def->label = L("Interface use loop pattern");
@@ -3318,14 +3339,17 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionString(""));
 
-    def = this->add("top_surface_line_width", coFloat);
+    def = this->add("top_surface_line_width", coFloatOrPercent);
     def->label = L("Top surface");
     def->category = L("Quality");
-    def->tooltip = L("Line width for top surfaces");
-    def->sidetext = L("mm");
+    def->tooltip = L("Line width for top surfaces. If expressed as a %, it will be computed over the nozzle diameter.");
+    def->sidetext = L("mm or %");
+    def->ratio_over = "nozzle_diameter";
     def->min = 0;
+    def->max = 1000;
+    def->max_literal = 10;
     def->mode = comAdvanced;
-    def->set_default_value(new ConfigOptionFloat(0.4));
+    def->set_default_value(new ConfigOptionFloatOrPercent(0., false));
 
     def = this->add("top_surface_speed", coFloat);
     def->label = L("Top surface");
@@ -4993,7 +5017,7 @@ std::map<std::string, std::string> validate(const FullPrintConfig &cfg, bool und
             "initial_layer_line_width" };
         for (size_t i = 0; i < sizeof(widths) / sizeof(widths[i]); ++ i) {
             std::string key(widths[i]);
-            if (cfg.get_abs_value(key) > 2.5 * max_nozzle_diameter) {
+            if (cfg.get_abs_value(key, max_nozzle_diameter) > 2.5 * max_nozzle_diameter) {
                 error_message.emplace(key, L("too large line width ") + std::to_string(cfg.get_abs_value(key)));
                 //return std::string("Too Large line width: ") + key;
             }
diff --git a/src/libslic3r/PrintConfig.hpp b/src/libslic3r/PrintConfig.hpp
index 1360b9c94f..6de2b12b6e 100644
--- a/src/libslic3r/PrintConfig.hpp
+++ b/src/libslic3r/PrintConfig.hpp
@@ -643,7 +643,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionBool,                bridge_no_support))
     ((ConfigOptionFloat,               elefant_foot_compensation))
     ((ConfigOptionFloat,               max_bridge_length))
-    ((ConfigOptionFloat,               line_width))
+    ((ConfigOptionFloatOrPercent,      line_width))
     // Force the generation of solid shells between adjacent materials/volumes.
     ((ConfigOptionBool,                interface_shells))
     ((ConfigOptionFloat,               layer_height))
@@ -667,7 +667,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionFloat,               support_bottom_z_distance))
     ((ConfigOptionInt,                 enforce_support_layers))
     ((ConfigOptionInt,                 support_filament))
-    ((ConfigOptionFloat,               support_line_width))
+    ((ConfigOptionFloatOrPercent,      support_line_width))
     ((ConfigOptionBool,                support_interface_loop_pattern))
     ((ConfigOptionInt,                 support_interface_filament))
     ((ConfigOptionInt,                 support_interface_top_layers))
@@ -727,7 +727,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionBool,                 ensure_vertical_shell_thickness))
     ((ConfigOptionEnum<InfillPattern>,  top_surface_pattern))
     ((ConfigOptionEnum<InfillPattern>,  bottom_surface_pattern))
-    ((ConfigOptionFloat,                outer_wall_line_width))
+    ((ConfigOptionFloatOrPercent,       outer_wall_line_width))
     ((ConfigOptionFloat,                outer_wall_speed))
     ((ConfigOptionFloat,                infill_direction))
     ((ConfigOptionPercent,              sparse_infill_density))
@@ -737,7 +737,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionFloat,                fuzzy_skin_point_distance))
     ((ConfigOptionFloat,                gap_infill_speed))
     ((ConfigOptionInt,                  sparse_infill_filament))
-    ((ConfigOptionFloat,                sparse_infill_line_width))
+    ((ConfigOptionFloatOrPercent,       sparse_infill_line_width))
     ((ConfigOptionPercent,              infill_wall_overlap))
     ((ConfigOptionFloat,                sparse_infill_speed))
     //BBS
@@ -750,17 +750,17 @@ PRINT_CONFIG_CLASS_DEFINE(
     // Detect bridging perimeters
     ((ConfigOptionBool, detect_overhang_wall))
     ((ConfigOptionInt, wall_filament))
-    ((ConfigOptionFloat, inner_wall_line_width))
+    ((ConfigOptionFloatOrPercent, inner_wall_line_width))
     ((ConfigOptionFloat, inner_wall_speed))
     // Total number of perimeters.
     ((ConfigOptionInt, wall_loops))
     ((ConfigOptionFloat, minimum_sparse_infill_area))
     ((ConfigOptionInt, solid_infill_filament))
-    ((ConfigOptionFloat, internal_solid_infill_line_width))
+    ((ConfigOptionFloatOrPercent, internal_solid_infill_line_width))
     ((ConfigOptionFloat, internal_solid_infill_speed))
     // Detect thin walls.
     ((ConfigOptionBool, detect_thin_wall))
-    ((ConfigOptionFloat, top_surface_line_width))
+    ((ConfigOptionFloatOrPercent, top_surface_line_width))
     ((ConfigOptionInt, top_shell_layers))
     ((ConfigOptionFloat, top_shell_thickness))
     ((ConfigOptionFloat, top_surface_speed))
@@ -946,7 +946,7 @@ PRINT_CONFIG_CLASS_DERIVED_DEFINE(
     ((ConfigOptionFloat,              travel_acceleration))
     ((ConfigOptionFloatOrPercent,     sparse_infill_acceleration))
     ((ConfigOptionFloatOrPercent,     internal_solid_infill_acceleration))
-    ((ConfigOptionFloat,              initial_layer_line_width))
+    ((ConfigOptionFloatOrPercent,     initial_layer_line_width))
     ((ConfigOptionFloat,              initial_layer_print_height))
     ((ConfigOptionFloat,              initial_layer_speed))
     ((ConfigOptionFloat,              default_jerk))
diff --git a/src/libslic3r/PrintObject.cpp b/src/libslic3r/PrintObject.cpp
index 890d7aab8a..f4e89957f7 100644
--- a/src/libslic3r/PrintObject.cpp
+++ b/src/libslic3r/PrintObject.cpp
@@ -423,7 +423,10 @@ static const float g_min_overhang_percent_for_lift = 0.3f;
 void PrintObject::detect_overhangs_for_lift()
 {
     if (this->set_started(posDetectOverhangsForLift)) {
-        const float min_overlap = m_config.line_width * g_min_overhang_percent_for_lift;
+        const double nozzle_diameter = m_print->config().nozzle_diameter.get_at(0);
+        const coordf_t line_width = this->config().get_abs_value("line_width", nozzle_diameter);
+
+        const float min_overlap = line_width * g_min_overhang_percent_for_lift;
         size_t num_layers = this->layer_count();
         size_t num_raft_layers = m_slicing_params.raft_layers();
 
@@ -433,14 +436,14 @@ void PrintObject::detect_overhangs_for_lift()
 
         tbb::spin_mutex layer_storage_mutex;
         tbb::parallel_for(tbb::blocked_range<size_t>(num_raft_layers + 1, num_layers),
-            [this, min_overlap](const tbb::blocked_range<size_t>& range)
+            [this, min_overlap, line_width](const tbb::blocked_range<size_t>& range)
             {
                 for (size_t layer_id = range.begin(); layer_id < range.end(); ++layer_id) {
                     Layer& layer = *m_layers[layer_id];
                     Layer& lower_layer = *layer.lower_layer;
 
                     ExPolygons overhangs = diff_ex(layer.lslices, offset_ex(lower_layer.lslices, scale_(min_overlap)));
-                    layer.loverhangs = std::move(offset2_ex(overhangs, -0.1f * scale_(m_config.line_width), 0.1f * scale_(m_config.line_width)));
+                    layer.loverhangs = std::move(offset2_ex(overhangs, -0.1f * scale_(line_width), 0.1f * scale_(line_width)));
                 }
             });
 
@@ -2591,6 +2594,7 @@ SupportNecessaryType PrintObject::is_support_necessary()
 #if 0
     double threshold_rad = (m_config.support_threshold_angle.value < EPSILON ? 30 : m_config.support_threshold_angle.value + 1) * M_PI / 180.;
     int enforce_support_layers = m_config.enforce_support_layers;
+    // not fixing in extrusion width % PR b/c never called 
     const coordf_t extrusion_width = m_config.line_width.value;
     const coordf_t extrusion_width_scaled = scale_(extrusion_width);
     float max_bridge_length = scale_(m_config.max_bridge_length.value);
diff --git a/src/libslic3r/PrintRegion.cpp b/src/libslic3r/PrintRegion.cpp
index 0f9f92e488..f3d5359f4c 100644
--- a/src/libslic3r/PrintRegion.cpp
+++ b/src/libslic3r/PrintRegion.cpp
@@ -21,7 +21,7 @@ unsigned int PrintRegion::extruder(FlowRole role) const
 Flow PrintRegion::flow(const PrintObject &object, FlowRole role, double layer_height, bool first_layer) const
 {
     const PrintConfig          &print_config = object.print()->config();
-    ConfigOptionFloat  config_width;
+    ConfigOptionFloatOrPercent config_width;
     // Get extrusion width from configuration.
     // (might be an absolute value, or a percent value, or zero for auto)
     if (first_layer && print_config.initial_layer_line_width.value > 0) {
diff --git a/src/libslic3r/SupportMaterial.cpp b/src/libslic3r/SupportMaterial.cpp
index 38b3a9d514..ecd48b46b4 100644
--- a/src/libslic3r/SupportMaterial.cpp
+++ b/src/libslic3r/SupportMaterial.cpp
@@ -2252,7 +2252,7 @@ PrintObjectSupportMaterial::MyLayersPtr PrintObjectSupportMaterial::top_contact_
 
     // check if the sharp tails should be extended higher
     bool detect_first_sharp_tail_only = false;
-    const coordf_t extrusion_width = m_object_config->line_width.value;
+    const coordf_t extrusion_width = m_object_config->line_width.get_abs_value(object.print()->config().nozzle_diameter.get_at(object.config().support_interface_filament-1));
     const coordf_t extrusion_width_scaled = scale_(extrusion_width);
     if (is_auto(m_object_config->support_type.value) && g_config_support_sharp_tails && !detect_first_sharp_tail_only) {
         for (size_t layer_nr = 0; layer_nr < object.layer_count(); layer_nr++) {
@@ -2345,7 +2345,7 @@ PrintObjectSupportMaterial::MyLayersPtr PrintObjectSupportMaterial::top_contact_
     // BBS group overhang clusters
     if (g_config_remove_small_overhangs) {
         std::vector<OverhangCluster> clusters;
-        double fw_scaled = scale_(m_object_config->line_width);
+      double fw_scaled = scale_(extrusion_width);
         std::set<ExPolygon*> removed_overhang;
 
         for (size_t layer_id = layer_id_start; layer_id < num_layers; layer_id++) {
diff --git a/src/libslic3r/TreeSupport.cpp b/src/libslic3r/TreeSupport.cpp
index f2309a930b..d2ebe11500 100644
--- a/src/libslic3r/TreeSupport.cpp
+++ b/src/libslic3r/TreeSupport.cpp
@@ -689,7 +689,12 @@ TreeSupport::TreeSupport(PrintObject& object, const SlicingParameters &slicing_p
         m_object_config->support_interface_pattern == smipConcentric ?
         ipConcentric :
         (m_support_params.interface_density > 0.95 ? ipRectilinear : ipSupportBase);
-    m_support_params.support_extrusion_width = m_object_config->support_line_width.value > 0 ? m_object_config->support_line_width : m_object_config->line_width;
+
+    const auto nozzle_diameter = object.print()->config().nozzle_diameter.get_at(object.config().support_interface_filament-1);
+    const coordf_t extrusion_width = m_object_config->line_width.get_abs_value(nozzle_diameter);
+    const coordf_t support_extrusion_width = m_object_config->support_line_width.get_abs_value(nozzle_diameter);
+
+    m_support_params.support_extrusion_width = support_extrusion_width > 0 ? support_extrusion_width : extrusion_width;
     is_slim                                  = is_tree_slim(support_type, support_style);
     is_strong = is_tree(support_type) && support_style == smsTreeStrong;
     MAX_BRANCH_RADIUS                        = 10.0;
@@ -723,7 +728,8 @@ void TreeSupport::detect_overhangs(bool detect_first_sharp_tail_only)
     const PrintObjectConfig& config = m_object->config();
     SupportType stype = support_type;
     const coordf_t radius_sample_resolution = g_config_tree_support_collision_resolution;
-    const coordf_t extrusion_width = config.line_width.value;
+    const double nozzle_diameter = m_object->print()->config().nozzle_diameter.get_at(0);
+    const coordf_t extrusion_width = config.get_abs_value("line_width", nozzle_diameter);
     const coordf_t extrusion_width_scaled = scale_(extrusion_width);
     const coordf_t max_bridge_length = scale_(config.max_bridge_length.value);
     const bool bridge_no_support = max_bridge_length > 0;
@@ -2011,7 +2017,8 @@ void TreeSupport::draw_circles(const std::vector<std::vector<Node*>>& contact_no
     const size_t   top_interface_layers = config.support_interface_top_layers.value;
     const size_t   bottom_interface_layers = config.support_interface_bottom_layers.value;
     const double diameter_angle_scale_factor = tan(tree_support_branch_diameter_angle * M_PI / 180.);// * layer_height / branch_radius; //Scale factor per layer to produce the desired angle.
-    const coordf_t line_width = config.support_line_width;
+    const double nozzle_diameter = m_object->print()->config().nozzle_diameter.get_at(0);
+    const coordf_t line_width = config.get_abs_value("support_line_width", nozzle_diameter);
     const coordf_t line_width_scaled           = scale_(line_width);
 
     const bool with_lightning_infill = m_support_params.base_fill_pattern == ipLightning;
@@ -2472,12 +2479,14 @@ void TreeSupport::drop_nodes(std::vector<std::vector<Node*>>& contact_nodes)
     const size_t bottom_interface_layers = config.support_interface_bottom_layers.value;
     const size_t top_interface_layers = config.support_interface_top_layers.value;
     float        DO_NOT_MOVER_UNDER_MM       = is_slim ? 0 : 5;                     // do not move contact points under 5mm
+    const auto nozzle_diameter = m_object->print()->config().nozzle_diameter.get_at(m_object->config().support_interface_filament-1);
+    const auto support_line_width = config.support_line_width.get_abs_value(nozzle_diameter);
 
     auto get_branch_angle = [this,&config](coordf_t radius) {
         if (config.tree_support_branch_angle.value < 30.0) return config.tree_support_branch_angle.value;
         return (radius - MIN_BRANCH_RADIUS) / (MAX_BRANCH_RADIUS - MIN_BRANCH_RADIUS) * (config.tree_support_branch_angle.value - 30.0) + 30.0;
     };
-    auto get_max_move_dist = [this, &config, branch_radius, tip_layers, diameter_angle_scale_factor, wall_count, support_extrusion_width](const Node *node, int power = 1) {
+    auto get_max_move_dist = [this, &config, branch_radius, tip_layers, diameter_angle_scale_factor, wall_count, support_extrusion_width, support_line_width](const Node *node, int power = 1) {
         double move_dist = node->max_move_dist;
         if (node->max_move_dist == 0) {
             if (node->radius == 0) node->radius = calc_branch_radius(branch_radius, node->dist_mm_to_top, diameter_angle_scale_factor);
@@ -2485,7 +2494,7 @@ void TreeSupport::drop_nodes(std::vector<std::vector<Node*>>& contact_nodes)
             if (angle > 30.0 && node->radius > MIN_BRANCH_RADIUS)
                 angle = (node->radius - MIN_BRANCH_RADIUS) / (MAX_BRANCH_RADIUS - MIN_BRANCH_RADIUS) * (config.tree_support_branch_angle.value - 30.0) + 30.0;
             double tan_angle           = tan(angle * M_PI / 180);
-            int wall_count_     = node->radius > 2 * config.support_line_width ? wall_count : 1;
+            int wall_count_     = node->radius > 2 * support_line_width ? wall_count : 1;
             node->max_move_dist = (angle < 90) ? (coordf_t) (tan_angle * node->height) * wall_count_ : std::numeric_limits<coordf_t>::max();
             node->max_move_dist        = std::min(node->max_move_dist, support_extrusion_width);
             move_dist           = node->max_move_dist;
diff --git a/src/libslic3r/calib.hpp b/src/libslic3r/calib.hpp
index 986442c0fe..9f31e002c6 100644
--- a/src/libslic3r/calib.hpp
+++ b/src/libslic3r/calib.hpp
@@ -166,8 +166,8 @@ public:
 protected:
     double speed_first_layer() const { return m_config.option<ConfigOptionFloat>("initial_layer_speed")->value; };
     double speed_perimeter() const { return m_config.option<ConfigOptionFloat>("outer_wall_speed")->value; };
-    double line_width_first_layer() const { return m_config.option<ConfigOptionFloat>("initial_layer_line_width")->value; };
-    double line_width() const { return m_config.option<ConfigOptionFloat>("line_width")->value; };
+    double line_width_first_layer() const { return m_config.get_abs_value("initial_layer_line_width"); };
+    double line_width() const { return m_config.get_abs_value("line_width"); };
     int wall_count() const { return m_config.option<ConfigOptionInt>("wall_loops")->value; };
 
 private:
diff --git a/src/slic3r/GUI/ConfigWizard.cpp b/src/slic3r/GUI/ConfigWizard.cpp
index 4a6eecbaad..24bf3a06ed 100644
--- a/src/slic3r/GUI/ConfigWizard.cpp
+++ b/src/slic3r/GUI/ConfigWizard.cpp
@@ -1390,7 +1390,7 @@ void PageDiameters::apply_custom_config(DynamicPrintConfig &config)
     auto set_extrusion_width = [&config, opt_nozzle](const char *key, double dmr) {
         char buf[64]; // locales don't matter here (sprintf/atof)
         sprintf(buf, "%.2lf", dmr * opt_nozzle->values.front() / 0.4);
-        config.set_key_value(key, new ConfigOptionFloat(atof(buf)));
+        config.set_key_value(key, new ConfigOptionFloatOrPercent(atof(buf),false));
     };
 
     set_extrusion_width("support_line_width", 0.35);
diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index 93ae0802c2..e6f05a0f4c 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -1,4 +1,5 @@
 #include "Plater.hpp"
+#include "libslic3r/Config.hpp"
 
 #include <cstddef>
 #include <algorithm>
@@ -8155,7 +8156,7 @@ void Plater::_calib_pa_pattern(const Calib_Params& params)
         double nozzle_diameter = printer_config.option<ConfigOptionFloats>("nozzle_diameter")->get_at(0);
         print_config.set_key_value(
             opt.first,
-            new ConfigOptionFloat(nozzle_diameter * opt.second / 100)
+            new ConfigOptionFloatOrPercent(nozzle_diameter * opt.second / 100, false)
         );
     }
 
@@ -8333,8 +8334,8 @@ void Plater::calib_flowrate(int pass) {
         _obj->config.set_key_value("detect_thin_wall", new ConfigOptionBool(true));
         _obj->config.set_key_value("filter_out_gap_fill", new ConfigOptionFloat(0));
         _obj->config.set_key_value("sparse_infill_pattern", new ConfigOptionEnum<InfillPattern>(ipRectilinear));
-        _obj->config.set_key_value("top_surface_line_width", new ConfigOptionFloat(nozzle_diameter * 1.2f));
-        _obj->config.set_key_value("internal_solid_infill_line_width", new ConfigOptionFloat(nozzle_diameter * 1.2f));
+        _obj->config.set_key_value("top_surface_line_width", new ConfigOptionFloatOrPercent(nozzle_diameter * 1.2f, false));
+        _obj->config.set_key_value("internal_solid_infill_line_width", new ConfigOptionFloatOrPercent(nozzle_diameter * 1.2f, false));
         _obj->config.set_key_value("top_surface_pattern", new ConfigOptionEnum<InfillPattern>(ipMonotonic));
         _obj->config.set_key_value("top_solid_infill_flow_ratio", new ConfigOptionFloat(1.0f));
         _obj->config.set_key_value("top_surface_pattern", new ConfigOptionEnum<InfillPattern>(ipMonotonic));
@@ -8455,7 +8456,7 @@ void Plater::calib_max_vol_speed(const Calib_Params& params)
     print_config->set_key_value("bottom_shell_layers", new ConfigOptionInt(1));
     print_config->set_key_value("sparse_infill_density", new ConfigOptionPercent(0));
     print_config->set_key_value("spiral_mode", new ConfigOptionBool(true));
-    print_config->set_key_value("outer_wall_line_width", new ConfigOptionFloat(line_width));
+    print_config->set_key_value("outer_wall_line_width", new ConfigOptionFloatOrPercent(line_width, false));
     print_config->set_key_value("initial_layer_print_height", new ConfigOptionFloat(layer_height));
     print_config->set_key_value("layer_height", new ConfigOptionFloat(layer_height));
     obj->config.set_key_value("brim_type", new ConfigOptionEnum<BrimType>(btOuterAndInner));