Wipe tower: changed the way how initial wipe tower preview depth is calculated

src/libslic3r/GCode/WipeTower.cpp

@@ -1346,6 +1346,31 @@ std::pair<double, double> WipeTower::get_wipe_tower_cone_base(double width, doub
     return std::make_pair(R, support_scale);
 }
 
+// Static method to extract wipe_volumes[from][to] from the configuration.
+std::vector<std::vector<float>> WipeTower::extract_wipe_volumes(const PrintConfig& config)
+{
+    // Get wiping matrix to get number of extruders and convert vector<double> to vector<float>:
+    std::vector<float> wiping_matrix(cast<float>(config.wiping_volumes_matrix.values));
+
+    // Extract purging volumes for each extruder pair:
+    std::vector<std::vector<float>> wipe_volumes;
+    const unsigned int number_of_extruders = (unsigned int)(sqrt(wiping_matrix.size())+EPSILON);
+    for (unsigned int i = 0; i<number_of_extruders; ++i)
+        wipe_volumes.push_back(std::vector<float>(wiping_matrix.begin()+i*number_of_extruders, wiping_matrix.begin()+(i+1)*number_of_extruders));
+
+    // Also include filament_minimal_purge_on_wipe_tower. This is needed for the preview.
+    for (unsigned int i = 0; i<number_of_extruders; ++i) {
+        for (unsigned int j = 0; j<number_of_extruders; ++j) {
+            float w = wipe_volumes[i][j];
+
+            if (wipe_volumes[i][j] < config.filament_minimal_purge_on_wipe_tower.get_at(j))
+                wipe_volumes[i][j] = config.filament_minimal_purge_on_wipe_tower.get_at(j);
+        }
+    }
+
+    return wipe_volumes;
+}
+
 // Appends a toolchange into m_plan and calculates neccessary depth of the corresponding box
 void WipeTower::plan_toolchange(float z_par, float layer_height_par, unsigned int old_tool,
                                 unsigned int new_tool, float wipe_volume)

src/libslic3r/GCode/WipeTower.hpp

@@ -22,8 +22,8 @@ class WipeTower
 {
 public:
     static const std::string never_skip_tag() { return "_GCODE_WIPE_TOWER_NEVER_SKIP_TAG"; }
-
 	static std::pair<double, double> get_wipe_tower_cone_base(double width, double height, double depth, double angle_deg);
+	static std::vector<std::vector<float>> extract_wipe_volumes(const PrintConfig& config);
 
     struct Extrusion
     {

src/libslic3r/Print.cpp

@@ -1337,11 +1337,22 @@ const WipeTowerData& Print::wipe_tower_data(size_t extruders_cnt) const
 {
     // If the wipe tower wasn't created yet, make sure the depth and brim_width members are set to default.
     if (! is_step_done(psWipeTower) && extruders_cnt !=0) {
+        const_cast<Print*>(this)->m_wipe_tower_data.brim_width = m_config.wipe_tower_brim_width;
+
+        // Calculating depth should take into account currently set wiping volumes.
+        // For a long time, the initial preview would just use 900/width per toolchange (15mm on a 60mm wide tower)
+        // and it worked well enough. Let's try to do slightly better by accounting for the purging volumes.
+        std::vector<std::vector<float>> wipe_volumes = WipeTower::extract_wipe_volumes(m_config);
+        std::vector<float> max_wipe_volumes;
+        for (const std::vector<float>& v : wipe_volumes)
+            max_wipe_volumes.emplace_back(*std::max_element(v.begin(), v.end()));
+        float maximum = std::accumulate(max_wipe_volumes.begin(), max_wipe_volumes.end(), 0.f);
+        maximum = maximum * extruders_cnt / max_wipe_volumes.size();
 
         float width = float(m_config.wipe_tower_width);
+        float layer_height = 0.2f; // just assume fixed value, it will still be better than before.
 
-        const_cast<Print*>(this)->m_wipe_tower_data.depth = (900.f/width) * float(extruders_cnt - 1);
-        const_cast<Print*>(this)->m_wipe_tower_data.brim_width = m_config.wipe_tower_brim_width;
+        const_cast<Print*>(this)->m_wipe_tower_data.depth = (maximum/layer_height)/width;
     }
 
     return m_wipe_tower_data;
@@ -1353,13 +1364,7 @@ void Print::_make_wipe_tower()
     if (! this->has_wipe_tower())
         return;
 
-    // Get wiping matrix to get number of extruders and convert vector<double> to vector<float>:
-    std::vector<float> wiping_matrix(cast<float>(m_config.wiping_volumes_matrix.values));
-    // Extract purging volumes for each extruder pair:
-    std::vector<std::vector<float>> wipe_volumes;
-    const unsigned int number_of_extruders = (unsigned int)(sqrt(wiping_matrix.size())+EPSILON);
-    for (unsigned int i = 0; i<number_of_extruders; ++i)
-        wipe_volumes.push_back(std::vector<float>(wiping_matrix.begin()+i*number_of_extruders, wiping_matrix.begin()+(i+1)*number_of_extruders));
+    std::vector<std::vector<float>> wipe_volumes = WipeTower::extract_wipe_volumes(m_config);
 
     // Let the ToolOrdering class know there will be initial priming extrusions at the start of the print.
     m_wipe_tower_data.tool_ordering = ToolOrdering(*this, (unsigned int)-1, true);
@@ -1412,7 +1417,7 @@ void Print::_make_wipe_tower()
     //wipe_tower.set_zhop();
 
     // Set the extruder & material properties at the wipe tower object.
-    for (size_t i = 0; i < number_of_extruders; ++ i)
+    for (size_t i = 0; i < m_config.nozzle_diameter.size(); ++ i)
         wipe_tower.set_extruder(i, m_config);
 
     m_wipe_tower_data.priming = Slic3r::make_unique<std::vector<WipeTower::ToolChangeResult>>(

src/slic3r/GUI/3DScene.cpp

@@ -488,8 +488,6 @@ int GLVolumeCollection::load_wipe_tower_preview(
     float rotation_angle, bool size_unknown, float brim_width)
 #endif // ENABLE_OPENGL_ES
 {
-    if (depth < 0.01f)
-        return int(this->volumes.size() - 1);
     if (height == 0.0f)
         height = 0.1f;