With single_extruder_multi_material enabled,

don't append a tool selection (Txx) to the extruder temperature
settings (M104 and M109).

xs/src/libslic3r/GCode.cpp

@@ -511,7 +511,7 @@ bool GCode::do_export(FILE *file, Print &print)
     }
     
     // Calculate wiping points if needed
-    if (print.config.ooze_prevention.value) {
+    if (print.config.ooze_prevention.value && ! print.config.single_extruder_multi_material) {
         Points skirt_points;
         for (const ExtrusionEntity *ee : print.skirt.entities)
             for (const ExtrusionPath &path : dynamic_cast<const ExtrusionLoop*>(ee)->paths)
@@ -680,8 +680,6 @@ void GCode::_print_first_layer_extruder_temperatures(FILE *file, Print &print, u
         if (print.config.single_extruder_multi_material.value) {
             // Set temperature of the first printing extruder only.
             int temp = print.config.first_layer_temperature.get_at(first_printing_extruder_id);
-            if (print.config.ooze_prevention.value)
-                temp += print.config.standby_temperature_delta.value;
             if (temp > 0)
                 write(file, m_writer.set_temperature(temp, wait, first_printing_extruder_id));
         } else {
@@ -1985,7 +1983,7 @@ std::string GCode::set_extruder(unsigned int extruder_id)
     m_wipe.reset_path();
     
     // append custom toolchange G-code
-    if (m_writer.extruder() != NULL && !m_config.toolchange_gcode.value.empty()) {
+    if (m_writer.extruder() != nullptr && !m_config.toolchange_gcode.value.empty()) {
         PlaceholderParser pp = m_placeholder_parser;
         pp.set("previous_extruder", m_writer.extruder()->id);
         pp.set("next_extruder",     extruder_id);
@@ -1994,7 +1992,7 @@ std::string GCode::set_extruder(unsigned int extruder_id)
     
     // if ooze prevention is enabled, park current extruder in the nearest
     // standby point and set it to the standby temperature
-    if (m_ooze_prevention.enable && m_writer.extruder() != NULL)
+    if (m_ooze_prevention.enable && m_writer.extruder() != nullptr)
         gcode += m_ooze_prevention.pre_toolchange(*this);
     // append the toolchange command
     gcode += m_writer.toolchange(extruder_id);

xs/src/libslic3r/GCodeWriter.cpp

@@ -13,15 +13,14 @@
 
 namespace Slic3r {
 
-void
+void GCodeWriter::apply_print_config(const PrintConfig &print_config)
-GCodeWriter::apply_print_config(const PrintConfig &print_config)
 {
     this->config.apply(print_config, true);
     this->_extrusion_axis = this->config.get_extrusion_axis();
+    this->m_single_extruder_multi_material = print_config.single_extruder_multi_material.value;
 }
 
-void
+void GCodeWriter::set_extruders(const std::vector<unsigned int> &extruder_ids)
-GCodeWriter::set_extruders(const std::vector<unsigned int> &extruder_ids)
 {
     for (unsigned int extruder_id : extruder_ids)
         this->extruders.insert(Extruder(extruder_id, &this->config));
@@ -32,8 +31,7 @@ GCodeWriter::set_extruders(const std::vector<unsigned int> &extruder_ids)
     this->multiple_extruders = (*std::max_element(extruder_ids.begin(), extruder_ids.end())) > 0;
 }
 
-std::string
+std::string GCodeWriter::preamble()
-GCodeWriter::preamble()
 {
     std::ostringstream gcode;
     
@@ -53,8 +51,7 @@ GCodeWriter::preamble()
     return gcode.str();
 }
 
-std::string
+std::string GCodeWriter::postamble() const
-GCodeWriter::postamble() const
 {
     std::ostringstream gcode;
     if (FLAVOR_IS(gcfMachinekit))
@@ -62,8 +59,7 @@ GCodeWriter::postamble() const
     return gcode.str();
 }
 
-std::string
+std::string GCodeWriter::set_temperature(unsigned int temperature, bool wait, int tool) const
-GCodeWriter::set_temperature(unsigned int temperature, bool wait, int tool) const
 {
     if (wait && (FLAVOR_IS(gcfMakerWare) || FLAVOR_IS(gcfSailfish)))
         return "";
@@ -85,7 +81,9 @@ GCodeWriter::set_temperature(unsigned int temperature, bool wait, int tool) cons
         gcode << "S";
     }
     gcode << temperature;
-    if (tool != -1 && (this->multiple_extruders || FLAVOR_IS(gcfMakerWare) || FLAVOR_IS(gcfSailfish))) {
+    if (tool != -1 && 
+        ( (this->multiple_extruders && ! this->m_single_extruder_multi_material) ||
+          FLAVOR_IS(gcfMakerWare) || FLAVOR_IS(gcfSailfish)) ) {
         gcode << " T" << tool;
     }
     gcode << " ; " << comment << "\n";
@@ -96,8 +94,7 @@ GCodeWriter::set_temperature(unsigned int temperature, bool wait, int tool) cons
     return gcode.str();
 }
 
-std::string
+std::string GCodeWriter::set_bed_temperature(unsigned int temperature, bool wait) const
-GCodeWriter::set_bed_temperature(unsigned int temperature, bool wait) const
 {
     std::string code, comment;
     if (wait && FLAVOR_IS_NOT(gcfTeacup)) {

xs/src/libslic3r/GCodeWriter.hpp

@@ -17,6 +17,7 @@ public:
     
     GCodeWriter() : 
         multiple_extruders(false), _extrusion_axis("E"), _extruder(nullptr),
+        m_single_extruder_multi_material(false),
         _last_acceleration(0), _last_fan_speed(0), _lifted(0)
         {}
     Extruder*   extruder() { return this->_extruder; }
@@ -61,12 +62,13 @@ public:
 
 private:
     std::string     _extrusion_axis;
+    bool            m_single_extruder_multi_material;
     Extruder*       _extruder;
     unsigned int    _last_acceleration;
     unsigned int    _last_fan_speed;
     double          _lifted;
     Pointf3         _pos;
-    
+
     std::string _travel_to_z(double z, const std::string &comment);
     std::string _retract(double length, double restart_extra, const std::string &comment);
 };