diff --git a/src/libslic3r/GCode.cpp b/src/libslic3r/GCode.cpp
index 219f6dbe3..b1ef5abf5 100644
--- a/src/libslic3r/GCode.cpp
+++ b/src/libslic3r/GCode.cpp
@@ -583,9 +583,9 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
         // We want to rotate and shift all extrusions (gcode postprocessing) and starting and ending position
         float alpha = m_wipe_tower_rotation / 180.f * float(M_PI);
 
-        auto transform_wt_pt = [&alpha, this](const Vec2f& pt) -> Vec2f {
+        auto transform_wt_pt = [&alpha, this](const Vec2f& pt,bool rib_offset=true) -> Vec2f {
             Vec2f out = Eigen::Rotation2Df(alpha) * pt;
-            out += m_wipe_tower_pos + m_rib_offset;
+            out += m_wipe_tower_pos + (rib_offset? m_rib_offset:Vec2f(0.f,0.f));
             return out;
         };
 
@@ -824,7 +824,7 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
                     avoid_bbx = scaled(m_wipe_tower_bbx);
                     Polygon avoid_points = avoid_bbx.polygon();
                     for (auto& p : avoid_points.points) {
-                        Vec2f pp = transform_wt_pt(unscale(p).cast<float>());
+                        Vec2f pp = transform_wt_pt(unscale(p).cast<float>(),false);
                         p = wipe_tower_point_to_object_point(gcodegen, pp + plate_origin_2d);
                     }
                     avoid_bbx = BoundingBox(avoid_points.points);
diff --git a/src/libslic3r/GCode/WipeTower.hpp b/src/libslic3r/GCode/WipeTower.hpp
index ca4c73a6c..aa32b231b 100644
--- a/src/libslic3r/GCode/WipeTower.hpp
+++ b/src/libslic3r/GCode/WipeTower.hpp
@@ -190,6 +190,7 @@ public:
     BoundingBoxf get_bbx() const {
         BoundingBox  box = get_extents(m_outer_wall.front());
         BoundingBoxf res = BoundingBoxf(unscale(box.min), unscale(box.max));
+        res.translate(m_rib_offset.cast<double>());
         return res;
     }
     Polylines get_outer_wall() const {
diff --git a/src/libslic3r/Print.cpp b/src/libslic3r/Print.cpp
index 2fc8d64e9..d4e2658f2 100644
--- a/src/libslic3r/Print.cpp
+++ b/src/libslic3r/Print.cpp
@@ -2287,9 +2287,9 @@ std::vector<Point> Print::first_layer_wipe_tower_corners(bool check_wipe_tower_e
     if (check_wipe_tower_existance && (!has_wipe_tower() || m_wipe_tower_data.tool_changes.empty()))
         return corners;
     {
-        double width = m_config.prime_tower_width + 2*m_wipe_tower_data.brim_width;
-        double depth = m_wipe_tower_data.depth + 2*m_wipe_tower_data.brim_width;
-        Vec2d pt0(-m_wipe_tower_data.brim_width, -m_wipe_tower_data.brim_width);
+        double width = m_wipe_tower_data.bbx.max.x() - m_wipe_tower_data.bbx.min.x();
+        double depth = m_wipe_tower_data.bbx.max.y() -m_wipe_tower_data.bbx.min.y();
+        Vec2d pt0 = m_wipe_tower_data.bbx.min;
         for (Vec2d pt : {
                 pt0,
                 Vec2d(pt0.x()+width, pt0.y()      ),