Add extrusion rate variance percent parameter for cura Arachne.

9 files changed, 157 insertions, 72 deletions

diff --git a/ArcWelder/arc_welder.cpp b/ArcWelder/arc_welder.cpp
index c49f64d..a1f4ca7 100644
--- a/ArcWelder/arc_welder.cpp
+++ b/ArcWelder/arc_welder.cpp
@@ -49,6 +49,7 @@ arc_welder::arc_welder(
 	bool allow_dynamic_precision,
 	unsigned char default_xyz_precision,
 	unsigned char default_e_precision,
+	double extrusion_rate_variance_percent,
 	int buffer_size, 
 	progress_callback callback) : current_arc_(
 			DEFAULT_MIN_SEGMENTS, 
@@ -83,6 +84,7 @@ arc_welder::arc_welder(
 	gcode_position_args_ = get_args_(g90_g91_influences_extruder, buffer_size);
 	allow_3d_arcs_ = allow_3d_arcs;
 	allow_dynamic_precision_ = allow_dynamic_precision;
+	extrusion_rate_variance_percent_ = extrusion_rate_variance_percent;
 	notification_period_seconds = 1;
 	lines_processed_ = 0;
 	gcodes_processed_ = 0;
@@ -93,6 +95,7 @@ arc_welder::arc_welder(
 	waiting_for_arc_ = false;
 	previous_feedrate_ = -1;
 	gcode_position_args_.set_num_extruders(8);
+	previous_extrusion_rate_ = 0;
 	for (int index = 0; index < 8; index++)
 	{
 		gcode_position_args_.retraction_lengths[0] = .0001;
@@ -399,6 +402,7 @@ int arc_welder::process_gcode(parsed_command cmd, bool is_end, bool is_reprocess
 	bool is_previous_extruder_relative = p_pre_pos->is_extruder_relative;
 	extruder extruder_current = p_cur_pos->get_current_extruder();
 	extruder previous_extruder = p_pre_pos->get_current_extruder();
+
 	//std::cout << lines_processed_ << " - " << cmd.gcode << ", CurrentEAbsolute: " << cur_extruder.e <<", ExtrusionLength: " << cur_extruder.extrusion_length << ", Retraction Length: " << cur_extruder.retraction_length << ", IsExtruding: " << cur_extruder.is_extruding << ", IsRetracting: " << cur_extruder.is_retracting << ".\n";
 
 	int lines_written = 0;
@@ -425,6 +429,22 @@ int arc_welder::process_gcode(parsed_command cmd, bool is_end, bool is_reprocess
 		}
 	}
 
+	// calculate the extrusion rate (mm/mm) and see how much it changes
+	double mm_extruded_per_mm_travel = 0;
+	double extrusion_rate_change_percent = 0;
+	if (movement_length_mm > 0)
+	{
+		mm_extruded_per_mm_travel = extruder_current.e_relative / movement_length_mm;
+		if (previous_extrusion_rate_ > 0)
+		{
+			extrusion_rate_change_percent = std::fabs(utilities::get_percent_change(previous_extrusion_rate_, mm_extruded_per_mm_travel));
+		}
+	}
+	if (extrusion_rate_change_percent > extrusion_rate_variance_percent_)
+	{
+		std::cout << "Extrusion Rate Change Percent: " << extrusion_rate_change_percent << "\n";
+	}
+	
 	// We need to make sure the printer is using absolute xyz, is extruding, and the extruder axis mode is the same as that of the previous position
 	// TODO: Handle relative XYZ axis.  This is possible, but maybe not so important.
 	bool is_g1_g2 = cmd.command == "G0" || cmd.command == "G1";
@@ -458,6 +478,7 @@ int arc_welder::process_gcode(parsed_command cmd, bool is_end, bool is_reprocess
 			utilities::is_equal(p_cur_pos->x_firmware_offset, p_pre_pos->x_firmware_offset) &&
 			utilities::is_equal(p_cur_pos->y_firmware_offset, p_pre_pos->y_firmware_offset) &&
 			utilities::is_equal(p_cur_pos->z_firmware_offset, p_pre_pos->z_firmware_offset) &&
+			(previous_extrusion_rate_ == 0 || utilities::less_than_or_equal(extrusion_rate_change_percent, extrusion_rate_variance_percent_)) &&
 			!p_cur_pos->is_relative &&
 			(
 				!waiting_for_arc_ ||
@@ -511,86 +532,95 @@ int arc_welder::process_gcode(parsed_command cmd, bool is_end, bool is_reprocess
 			}
 		}
 	}
-	else if (debug_logging_enabled_ ){
-		if (is_end)
-		{
-			p_logger_->log(logger_type_, DEBUG, "Procesing final shape, if one exists.");
-		}
-		else if (!cmd.is_empty)
-		{
-			if (!cmd.is_known_command)
-			{
-				p_logger_->log(logger_type_, DEBUG, "Command '" + cmd.command + "' is Unknown.  Gcode:" + cmd.gcode);
-			}
-			else if (cmd.command != "G0" && cmd.command != "G1")
-			{
-				p_logger_->log(logger_type_, DEBUG, "Command '"+ cmd.command + "' is not G0/G1, skipping.  Gcode:" + cmd.gcode);
-			}
-			else if (!allow_3d_arcs_ && !utilities::is_equal(p_cur_pos->z, p_pre_pos->z))
+	else {
+		previous_extrusion_rate_ = 0;
+		if (debug_logging_enabled_) {
+			if (is_end)
 			{
-				p_logger_->log(logger_type_, DEBUG, "Z axis position changed, cannot convert:" + cmd.gcode);
+				p_logger_->log(logger_type_, DEBUG, "Procesing final shape, if one exists.");
 			}
-			else if (p_cur_pos->is_relative)
+			else if (!cmd.is_empty)
 			{
-				p_logger_->log(logger_type_, DEBUG, "XYZ Axis is in relative mode, cannot convert:" + cmd.gcode);
-			}
-			else if (
-				waiting_for_arc_ && !( 
-					(previous_extruder.is_extruding && extruder_current.is_extruding) ||
-					(previous_extruder.is_retracting && extruder_current.is_retracting)
-				)
-			)
-			{
-				std::string message = "Extruding or retracting state changed, cannot add point to current arc: " + cmd.gcode;
-				if (verbose_logging_enabled_)
+				if (!cmd.is_known_command)
 				{
-					
-					message.append(
-						" - Verbose Info\n\tCurrent Position Info - Absolute E:" + utilities::to_string(extruder_current.e) +
-						", Offset E:" + utilities::to_string(extruder_current.get_offset_e()) +
-						", Mode:" + (p_cur_pos->is_extruder_relative_null ? "NULL" : p_cur_pos->is_extruder_relative ? "relative" : "absolute") +
-						", Retraction: " + utilities::to_string(extruder_current.retraction_length) +
-						", Extrusion: " + utilities::to_string(extruder_current.extrusion_length) +
-						", Retracting: " + (extruder_current.is_retracting ? "True" : "False") +
-						", Extruding: " + (extruder_current.is_extruding ? "True" : "False")
-					);
-					message.append(
-						"\n\tPrevious Position Info - Absolute E:" + utilities::to_string(previous_extruder.e) +
-						", Offset E:" + utilities::to_string(previous_extruder.get_offset_e()) +
-						", Mode:" + (p_pre_pos->is_extruder_relative_null ? "NULL" : p_pre_pos->is_extruder_relative ? "relative" : "absolute") +
-						", Retraction: " + utilities::to_string(previous_extruder.retraction_length) +
-						", Extrusion: " + utilities::to_string(previous_extruder.extrusion_length) +
-						", Retracting: " + (previous_extruder.is_retracting ? "True" : "False") +
-						", Extruding: " + (previous_extruder.is_extruding ? "True" : "False")
-					);
-					p_logger_->log(logger_type_, VERBOSE, message);
+					p_logger_->log(logger_type_, DEBUG, "Command '" + cmd.command + "' is Unknown.  Gcode:" + cmd.gcode);
+				}
+				else if (cmd.command != "G0" && cmd.command != "G1")
+				{
+					p_logger_->log(logger_type_, DEBUG, "Command '" + cmd.command + "' is not G0/G1, skipping.  Gcode:" + cmd.gcode);
+				}
+				else if (!allow_3d_arcs_ && !utilities::is_equal(p_cur_pos->z, p_pre_pos->z))
+				{
+					p_logger_->log(logger_type_, DEBUG, "Z axis position changed, cannot convert:" + cmd.gcode);
+				}
+				else if (p_cur_pos->is_relative)
+				{
+					p_logger_->log(logger_type_, DEBUG, "XYZ Axis is in relative mode, cannot convert:" + cmd.gcode);
+				}
+				else if (
+					waiting_for_arc_ && !(
+						(previous_extruder.is_extruding && extruder_current.is_extruding) ||
+						(previous_extruder.is_retracting && extruder_current.is_retracting)
+						)
+					)
+				{
+					std::string message = "Extruding or retracting state changed, cannot add point to current arc: " + cmd.gcode;
+					if (verbose_logging_enabled_)
+					{
+
+						message.append(
+							" - Verbose Info\n\tCurrent Position Info - Absolute E:" + utilities::to_string(extruder_current.e) +
+							", Offset E:" + utilities::to_string(extruder_current.get_offset_e()) +
+							", Mode:" + (p_cur_pos->is_extruder_relative_null ? "NULL" : p_cur_pos->is_extruder_relative ? "relative" : "absolute") +
+							", Retraction: " + utilities::to_string(extruder_current.retraction_length) +
+							", Extrusion: " + utilities::to_string(extruder_current.extrusion_length) +
+							", Retracting: " + (extruder_current.is_retracting ? "True" : "False") +
+							", Extruding: " + (extruder_current.is_extruding ? "True" : "False")
+						);
+						message.append(
+							"\n\tPrevious Position Info - Absolute E:" + utilities::to_string(previous_extruder.e) +
+							", Offset E:" + utilities::to_string(previous_extruder.get_offset_e()) +
+							", Mode:" + (p_pre_pos->is_extruder_relative_null ? "NULL" : p_pre_pos->is_extruder_relative ? "relative" : "absolute") +
+							", Retraction: " + utilities::to_string(previous_extruder.retraction_length) +
+							", Extrusion: " + utilities::to_string(previous_extruder.extrusion_length) +
+							", Retracting: " + (previous_extruder.is_retracting ? "True" : "False") +
+							", Extruding: " + (previous_extruder.is_extruding ? "True" : "False")
+						);
+						p_logger_->log(logger_type_, VERBOSE, message);
+					}
+					else
+					{
+						p_logger_->log(logger_type_, DEBUG, message);
+					}
+
+				}
+				else if (p_cur_pos->is_extruder_relative != p_pre_pos->is_extruder_relative)
+				{
+					p_logger_->log(logger_type_, DEBUG, "Extruder axis mode changed, cannot add point to current arc: " + cmd.gcode);
+				}
+				else if (waiting_for_arc_ && p_pre_pos->f != p_cur_pos->f)
+				{
+					p_logger_->log(logger_type_, DEBUG, "Feedrate changed, cannot add point to current arc: " + cmd.gcode);
+				}
+				else if (waiting_for_arc_ && p_pre_pos->feature_type_tag != p_cur_pos->feature_type_tag)
+				{
+					p_logger_->log(logger_type_, DEBUG, "Feature type changed, cannot add point to current arc: " + cmd.gcode);
+				}
+				else if (previous_extrusion_rate_ != 0 && !utilities::is_equal(previous_extrusion_rate_, mm_extruded_per_mm_travel))
+				{
+					p_logger_->log(logger_type_, DEBUG, "Previus extrusion rate changed: " + cmd.gcode);
 				}
 				else
 				{
-					p_logger_->log(logger_type_, DEBUG, message);
+					// Todo:  Add all the relevant values
+					p_logger_->log(logger_type_, DEBUG, "There was an unknown issue preventing the current point from being added to the arc: " + cmd.gcode);
 				}
-				
-			}
-			else if (p_cur_pos->is_extruder_relative != p_pre_pos->is_extruder_relative)
-			{
-				p_logger_->log(logger_type_, DEBUG, "Extruder axis mode changed, cannot add point to current arc: " + cmd.gcode);
-			}
-			else if (waiting_for_arc_ && p_pre_pos->f != p_cur_pos->f)
-			{
-				p_logger_->log(logger_type_, DEBUG, "Feedrate changed, cannot add point to current arc: " + cmd.gcode);
-			}
-			else if (waiting_for_arc_ && p_pre_pos->feature_type_tag != p_cur_pos->feature_type_tag)
-			{
-				p_logger_->log(logger_type_, DEBUG, "Feature type changed, cannot add point to current arc: " + cmd.gcode);
-			}
-			else
-			{
-				// Todo:  Add all the relevant values
-				p_logger_->log(logger_type_, DEBUG, "There was an unknown issue preventing the current point from being added to the arc: " + cmd.gcode);
 			}
 		}
 	}
 	
+	previous_extrusion_rate_ = mm_extruded_per_mm_travel;
+
 	if (!arc_added && !(cmd.is_empty && cmd.comment.length() == 0))
 	{
 		if (current_arc_.get_num_segments() < current_arc_.get_min_segments()) {
@@ -837,7 +867,8 @@ void arc_welder::add_arcwelder_comment_to_target()
 		stream << "; allow_dynamic_precision=True\n";
 	}
 	stream << "; default_xyz_precision=" << std::setprecision(0) << static_cast<int>(current_arc_.get_xyz_precision()) << "\n";
-	stream << "; default_e_precision=" << std::setprecision(0) << static_cast<int>(current_arc_.get_e_precision()) << "\n\n";
+	stream << "; default_e_precision=" << std::setprecision(0) << static_cast<int>(current_arc_.get_e_precision()) << "\n";
+	stream << "; extrusion_rate_variance_percent=" << std::setprecision(3) << static_cast<int>(extrusion_rate_variance_percent_) << "%\n\n";
 
 	
 	output_file_ << stream.str();
diff --git a/ArcWelder/arc_welder.h b/ArcWelder/arc_welder.h
index 6d00ec4..2da8929 100644
--- a/ArcWelder/arc_welder.h
+++ b/ArcWelder/arc_welder.h
@@ -415,6 +415,8 @@ struct arc_welder_results {
 #define DEFAULT_GCODE_BUFFER_SIZE 1000
 #define DEFAULT_G90_G91_INFLUENCES_EXTRUDER false
 #define DEFAULT_ALLOW_DYNAMIC_PRECISION false
+#define DEFAULT_EXTRUSION_RATE_VARIANCE_PERCENT 1
+//#define DEFAULT_EXTRUSION_RATE_VARIANCE 0.0001
 class arc_welder
 {
 public:
@@ -432,6 +434,7 @@ public:
 		bool allow_dynamic_precision = DEFAULT_ALLOW_DYNAMIC_PRECISION,
 		unsigned char default_xyz_precision = DEFAULT_XYZ_PRECISION,
 		unsigned char default_e_precision = DEFAULT_E_PRECISION,
+		double extrusion_rate_variance_percent = DEFAULT_EXTRUSION_RATE_VARIANCE_PERCENT,
 		int buffer_size = DEFAULT_GCODE_BUFFER_SIZE,
 		progress_callback callback = NULL);
 	void set_logger_type(int logger_type);
@@ -478,6 +481,8 @@ private:
 	// We don't care about the printer settings, except for g91 influences extruder.
 	gcode_position* p_source_position_;
 	double previous_feedrate_;
+	double previous_extrusion_rate_;
+	double extrusion_rate_variance_percent_;
 	gcode_parser parser_;
 	bool verbose_output_;
 	int logger_type_;
diff --git a/ArcWelderConsole/ArcWelderConsole.cpp b/ArcWelderConsole/ArcWelderConsole.cpp
index 0ebe847..691f155 100644
--- a/ArcWelderConsole/ArcWelderConsole.cpp
+++ b/ArcWelderConsole/ArcWelderConsole.cpp
@@ -50,6 +50,7 @@ int main(int argc, char* argv[])
   bool allow_dynamic_precision = DEFAULT_ALLOW_DYNAMIC_PRECISION;
   unsigned char default_xyz_precision = DEFAULT_XYZ_PRECISION;
   unsigned char default_e_precision = DEFAULT_E_PRECISION;
+  double extrusion_rate_variance_percent = DEFAULT_EXTRUSION_RATE_VARIANCE_PERCENT;
   std::string log_level_string;
   std::string log_level_string_default = "INFO";
   int log_level_value;
@@ -140,6 +141,13 @@ int main(int argc, char* argv[])
     arg_description_stream << "The default precision of E output gcode parameters.  The precision may be larger than this value if allow-dynamic-precision is set to true.  Default Value: " << DEFAULT_E_PRECISION;
     TCLAP::ValueArg<unsigned char> default_e_precision_arg("e", "default-e-precision", arg_description_stream.str(), false, DEFAULT_E_PRECISION, "unsigned char");
 
+    // -v --extrusion-rate-variance
+    arg_description_stream.clear();
+    arg_description_stream.str("");
+    arg_description_stream << "The allowed variance in extrusion rate by percent.  Default Value: " << DEFAULT_EXTRUSION_RATE_VARIANCE_PERCENT;
+    TCLAP::ValueArg<double> extrusion_rate_variance_percent_arg("v", "extrusion-rate-variance-percent", arg_description_stream.str(), false, DEFAULT_EXTRUSION_RATE_VARIANCE_PERCENT, "double");
+
+
     // -g --hide-progress
     TCLAP::SwitchArg hide_progress_arg("p", "hide-progress", "If supplied, prevents progress updates from being displayed.", false);
 
@@ -171,6 +179,7 @@ int main(int argc, char* argv[])
     cmd.add(allow_dynamic_precision_arg);
     cmd.add(default_xyz_precision_arg);
     cmd.add(default_e_precision_arg);
+    cmd.add(extrusion_rate_variance_percent_arg);
     cmd.add(g90_arg);
     cmd.add(hide_progress_arg);
     cmd.add(log_level_arg);
@@ -197,6 +206,7 @@ int main(int argc, char* argv[])
     allow_dynamic_precision = allow_dynamic_precision_arg.getValue();
     default_xyz_precision = default_xyz_precision_arg.getValue();
     default_e_precision = default_e_precision_arg.getValue();
+    extrusion_rate_variance_percent = extrusion_rate_variance_percent_arg.getValue();
 
     hide_progress = hide_progress_arg.getValue();
     log_level_string = log_level_arg.getValue();
@@ -275,6 +285,13 @@ int main(int argc, char* argv[])
       default_e_precision = 6;
     }
 
+    if (extrusion_rate_variance_percent < 0)
+    {
+      // warning
+      std::cout << "warning: The provided extrusion_rate_variance_percent " << extrusion_rate_variance_percent << " is less than 0.  Setting to the default." << std::endl;
+      extrusion_rate_variance_percent = DEFAULT_EXTRUSION_RATE_VARIANCE_PERCENT;
+    }
+
     if (has_error)
     {
       return 1;
@@ -353,6 +370,7 @@ int main(int argc, char* argv[])
   log_messages << "\tAllow Dynamic Precision      : " << (allow_dynamic_precision ? "True" : "False") << "\n";
   log_messages << "\tDefault XYZ Precision        : " << std::setprecision(0) << static_cast<int>(default_xyz_precision) << "\n";
   log_messages << "\tDefault E Precision          : " << std::setprecision(0) << static_cast<int>(default_e_precision) << "\n";
+  log_messages << "\tExtrusion Rate Variance %    : " << std::setprecision(3) << extrusion_rate_variance_percent << "%\n";
   log_messages << "\tG90/G91 Influences Extruder  : " << (g90_g91_influences_extruder ? "True" : "False") << "\n";
   log_messages << "\tLog Level                    : " << log_level_string << "\n";
   log_messages << "\tHide Progress Updates        : " << (hide_progress ? "True" : "False");
@@ -364,9 +382,9 @@ int main(int argc, char* argv[])
     target_file_path = temp_file_path;
   }
   if (!hide_progress)
-    p_arc_welder = new arc_welder(source_file_path, target_file_path, p_logger, resolution_mm, path_tolerance_percent, max_radius_mm, min_arc_segments, mm_per_arc_segment, g90_g91_influences_extruder, allow_3d_arcs, allow_dynamic_precision, default_xyz_precision, default_e_precision,  DEFAULT_GCODE_BUFFER_SIZE, on_progress);
+    p_arc_welder = new arc_welder(source_file_path, target_file_path, p_logger, resolution_mm, path_tolerance_percent, max_radius_mm, min_arc_segments, mm_per_arc_segment, g90_g91_influences_extruder, allow_3d_arcs, allow_dynamic_precision, default_xyz_precision, default_e_precision, extrusion_rate_variance_percent,  DEFAULT_GCODE_BUFFER_SIZE, on_progress);
   else
-    p_arc_welder = new arc_welder(source_file_path, target_file_path, p_logger, resolution_mm, path_tolerance_percent, max_radius_mm, min_arc_segments, mm_per_arc_segment, g90_g91_influences_extruder, allow_3d_arcs, allow_dynamic_precision, default_xyz_precision, default_e_precision, DEFAULT_GCODE_BUFFER_SIZE, suppress_progress);
+    p_arc_welder = new arc_welder(source_file_path, target_file_path, p_logger, resolution_mm, path_tolerance_percent, max_radius_mm, min_arc_segments, mm_per_arc_segment, g90_g91_influences_extruder, allow_3d_arcs, allow_dynamic_precision, default_xyz_precision, default_e_precision, extrusion_rate_variance_percent, DEFAULT_GCODE_BUFFER_SIZE, suppress_progress);
 
   arc_welder_results results = p_arc_welder->process();
   if (results.success)
diff --git a/ArcWelderTest/ArcWelderTest.cpp b/ArcWelderTest/ArcWelderTest.cpp
index 9add004..3cb916c 100644
--- a/ArcWelderTest/ArcWelderTest.cpp
+++ b/ArcWelderTest/ArcWelderTest.cpp
@@ -305,6 +305,7 @@ static void TestAntiStutter(std::string filePath)
 		DEFAULT_ALLOW_DYNAMIC_PRECISION,
 		DEFAULT_XYZ_PRECISION,
 		DEFAULT_E_PRECISION,
+		DEFAULT_EXTRUSION_RATE_VARIANCE_PERCENT,
 		DEFAULT_GCODE_BUFFER_SIZE, 
 		on_progress);
 	//FIRMWARE_COMPENSATION_TEST_1
diff --git a/GcodeProcessorLib/utilities.cpp b/GcodeProcessorLib/utilities.cpp
index dbe23fb..041f91f 100644
--- a/GcodeProcessorLib/utilities.cpp
+++ b/GcodeProcessorLib/utilities.cpp
@@ -171,6 +171,15 @@ double utilities::get_percent_change(int v1, int v2)
 	return 0;
 }
 
+double utilities::get_percent_change(double v1, double v2)
+{
+	if (v1 != 0)
+	{
+		return ((v2 - v1) / v1) * 100.0;
+	}
+	return 0;
+}
+
 std::string utilities::get_percent_change_string(int v1, int v2, int precision)
 {
 	std::stringstream format_stream;
diff --git a/GcodeProcessorLib/utilities.h b/GcodeProcessorLib/utilities.h
index 401bed4..b41d6f6 100644
--- a/GcodeProcessorLib/utilities.h
+++ b/GcodeProcessorLib/utilities.h
@@ -49,6 +49,7 @@ public:
 	static std::istream& safe_get_line(std::istream& is, std::string& t);
 	static std::string center(std::string input, int width);
 	static double get_percent_change(int v1, int v2);
+	static double get_percent_change(double v1, double v2);
 	static std::string get_percent_change_string(int v1, int v2, int precision);
 
 	static int get_num_digits(int x);
diff --git a/PyArcWelder/py_arc_welder.h b/PyArcWelder/py_arc_welder.h
index ed4e8cc..6813c34 100644
--- a/PyArcWelder/py_arc_welder.h
+++ b/PyArcWelder/py_arc_welder.h
@@ -49,6 +49,7 @@ public:
 		bool allow_dynamic_precision,
 		unsigned char default_xyz_precision,
 		unsigned char default_e_precision,
+		double extrusion_rate_variance_percent,
 		int buffer_size, 
 		PyObject* py_progress_callback
 		): arc_welder(
@@ -65,6 +66,7 @@ public:
 			allow_dynamic_precision,
 			default_xyz_precision,
 			default_e_precision,
+			extrusion_rate_variance_percent,
 			buffer_size
   ){
 		guid_ = guid;
diff --git a/PyArcWelder/py_arc_welder_extension.cpp b/PyArcWelder/py_arc_welder_extension.cpp
index 1e0728b..71c3855 100644
--- a/PyArcWelder/py_arc_welder_extension.cpp
+++ b/PyArcWelder/py_arc_welder_extension.cpp
@@ -210,6 +210,7 @@ extern "C"
 			args.allow_dynamic_precision, 
 			args.default_xyz_precision, 
 			args.default_e_precision, 
+			args.extrusion_rate_variance_percent,
 			DEFAULT_GCODE_BUFFER_SIZE, 
 			py_progress_callback
 		);
@@ -342,11 +343,25 @@ static bool ParseArgs(PyObject* py_args, py_gcode_arc_args& args, PyObject** py_
 		args.default_e_precision = 6;
 	}
 
+	// Extract the extrusion_rate_variance
+	PyObject* py_extrusion_rate_variance_percent = PyDict_GetItemString(py_args, "extrusion_rate_variance_percent");
+	if (py_extrusion_rate_variance_percent == NULL)
+	{
+		std::string message = "ParseArgs - Unable to retrieve the extrusion_rate_variance_percent parameter from the args.";
+		p_py_logger->log_exception(GCODE_CONVERSION, message);
+		return false;
+	}
+	args.extrusion_rate_variance_percent = gcode_arc_converter::PyFloatOrInt_AsDouble(py_extrusion_rate_variance_percent);
+	if (args.extrusion_rate_variance_percent < 0)
+	{
+		args.extrusion_rate_variance_percent = DEFAULT_EXTRUSION_RATE_VARIANCE_PERCENT; // Set to the default if no resolution is provided, or if it is less than 0.
+	}
+
 	// Extract the path tolerance_percent
 	PyObject* py_path_tolerance_percent = PyDict_GetItemString(py_args, "path_tolerance_percent");
 	if (py_path_tolerance_percent == NULL)
 	{
-		std::string message = "ParseArgs - Unable to retrieve the py_path_tolerance_percent parameter from the args.";
+		std::string message = "ParseArgs - Unable to retrieve the path_tolerance_percent parameter from the args.";
 		p_py_logger->log_exception(GCODE_CONVERSION, message);
 		return false;
 	}
diff --git a/PyArcWelder/py_arc_welder_extension.h b/PyArcWelder/py_arc_welder_extension.h
index 2c2ecec..9b979fe 100644
--- a/PyArcWelder/py_arc_welder_extension.h
+++ b/PyArcWelder/py_arc_welder_extension.h
@@ -69,6 +69,7 @@ struct py_gcode_arc_args {
 		bool allow_dynamic_precision_,
 		unsigned char default_xyz_precision_,
 		unsigned char default_e_precision_,
+		double extrusion_rate_variance_percent_,
 		int log_level_
 	) {
 		guid = guid_;
@@ -83,6 +84,7 @@ struct py_gcode_arc_args {
 		allow_dynamic_precision = allow_dynamic_precision_;
 		default_xyz_precision = default_xyz_precision_;
 		default_e_precision = default_e_precision_;
+		extrusion_rate_variance_percent = extrusion_rate_variance_percent_;
 		g90_g91_influences_extruder = g90_g91_influences_extruder_;
 		log_level = log_level_;
 	}
@@ -95,6 +97,7 @@ struct py_gcode_arc_args {
 	bool allow_dynamic_precision;
 	unsigned char default_xyz_precision;
 	unsigned char default_e_precision;
+	double extrusion_rate_variance_percent;
 	bool g90_g91_influences_extruder;
 	double max_radius_mm;
 	int min_arc_segments;