diff --git a/src/libslic3r/Model.cpp b/src/libslic3r/Model.cpp
index ed8be8ce5..cdea83fb7 100644
--- a/src/libslic3r/Model.cpp
+++ b/src/libslic3r/Model.cpp
@@ -1829,33 +1829,28 @@ arrangement::ArrangePolygon ModelInstance::get_arrange_polygon() const
 {
     static const double SIMPLIFY_TOLERANCE_MM = 0.1;
     
-    if (!m_arrange_cache.valid) {
-        Vec3d rotation = get_rotation();
-        rotation.z()   = 0.;
-        Transform3d trafo_instance =
-            Geometry::assemble_transform(Vec3d::Zero(), rotation,
-                                         get_scaling_factor(), get_mirror());
-    
-        Polygon p = get_object()->convex_hull_2d(trafo_instance);
-    
-        assert(!p.points.empty());
-    
-        // this may happen for malformed models, see:
-        // https://github.com/prusa3d/PrusaSlicer/issues/2209
-        if (!p.points.empty()) {
-            Polygons pp{p};
-            pp = p.simplify(scaled<double>(SIMPLIFY_TOLERANCE_MM));
-            if (!pp.empty()) p = pp.front();
-        }
-        
-        m_arrange_cache.poly.contour = std::move(p);
-        m_arrange_cache.valid = true;
-    }
+    Vec3d rotation = get_rotation();
+    rotation.z()   = 0.;
+    Transform3d trafo_instance =
+        Geometry::assemble_transform(Vec3d::Zero(), rotation,
+                                     get_scaling_factor(), get_mirror());
 
+    Polygon p = get_object()->convex_hull_2d(trafo_instance);
+
+    assert(!p.points.empty());
+
+    // this may happen for malformed models, see:
+    // https://github.com/prusa3d/PrusaSlicer/issues/2209
+    if (!p.points.empty()) {
+        Polygons pp{p};
+        pp = p.simplify(scaled<double>(SIMPLIFY_TOLERANCE_MM));
+        if (!pp.empty()) p = pp.front();
+    }
+   
     arrangement::ArrangePolygon ret;
-    ret.poly        = m_arrange_cache.poly;
-    ret.translation = Vec2crd{scaled(get_offset(X)), scaled(get_offset(Y))};
-    ret.rotation    = get_rotation(Z);
+    ret.poly.contour = std::move(p);
+    ret.translation  = Vec2crd{scaled(get_offset(X)), scaled(get_offset(Y))};
+    ret.rotation     = get_rotation(Z);
 
     return ret;
 }
diff --git a/src/libslic3r/Model.hpp b/src/libslic3r/Model.hpp
index f5786812f..008699818 100644
--- a/src/libslic3r/Model.hpp
+++ b/src/libslic3r/Model.hpp
@@ -555,7 +555,7 @@ public:
     ModelObject* get_object() const { return this->object; }
 
     const Geometry::Transformation& get_transformation() const { return m_transformation; }
-    void set_transformation(const Geometry::Transformation& transformation) { m_transformation = transformation; m_arrange_cache.valid = false; }
+    void set_transformation(const Geometry::Transformation& transformation) { m_transformation = transformation; }
 
     const Vec3d& get_offset() const { return m_transformation.get_offset(); }
     double get_offset(Axis axis) const { return m_transformation.get_offset(axis); }
@@ -566,21 +566,21 @@ public:
     const Vec3d& get_rotation() const { return m_transformation.get_rotation(); }
     double get_rotation(Axis axis) const { return m_transformation.get_rotation(axis); }
 
-    void set_rotation(const Vec3d& rotation) { m_transformation.set_rotation(rotation); m_arrange_cache.valid = false; }
-    void set_rotation(Axis axis, double rotation) { m_transformation.set_rotation(axis, rotation); if (axis != Z) m_arrange_cache.valid = false; }
+    void set_rotation(const Vec3d& rotation) { m_transformation.set_rotation(rotation); }
+    void set_rotation(Axis axis, double rotation) { m_transformation.set_rotation(axis, rotation); }
 
     const Vec3d& get_scaling_factor() const { return m_transformation.get_scaling_factor(); }
     double get_scaling_factor(Axis axis) const { return m_transformation.get_scaling_factor(axis); }
 
-    void set_scaling_factor(const Vec3d& scaling_factor) { m_transformation.set_scaling_factor(scaling_factor); m_arrange_cache.valid = false; }
-    void set_scaling_factor(Axis axis, double scaling_factor) { m_transformation.set_scaling_factor(axis, scaling_factor); m_arrange_cache.valid = false; }
+    void set_scaling_factor(const Vec3d& scaling_factor) { m_transformation.set_scaling_factor(scaling_factor); }
+    void set_scaling_factor(Axis axis, double scaling_factor) { m_transformation.set_scaling_factor(axis, scaling_factor); }
 
     const Vec3d& get_mirror() const { return m_transformation.get_mirror(); }
     double get_mirror(Axis axis) const { return m_transformation.get_mirror(axis); }
 	bool is_left_handed() const { return m_transformation.is_left_handed(); }
     
-    void set_mirror(const Vec3d& mirror) { m_transformation.set_mirror(mirror); m_arrange_cache.valid = false; }
-    void set_mirror(Axis axis, double mirror) { m_transformation.set_mirror(axis, mirror); m_arrange_cache.valid = false; }
+    void set_mirror(const Vec3d& mirror) { m_transformation.set_mirror(mirror); }
+    void set_mirror(Axis axis, double mirror) { m_transformation.set_mirror(axis, mirror); }
 
     // To be called on an external mesh
     void transform_mesh(TriangleMesh* mesh, bool dont_translate = false) const;
@@ -623,18 +623,10 @@ private:
     ModelObject* object;
 
     // Constructor, which assigns a new unique ID.
-    explicit ModelInstance(ModelObject *object) : print_volume_state(PVS_Inside), object(object)
-    {
-        assert(this->id().valid());
-        get_arrange_polygon(); // initialize the cache
-    }
+    explicit ModelInstance(ModelObject *object) : print_volume_state(PVS_Inside), object(object) { assert(this->id().valid()); }
     // Constructor, which assigns a new unique ID.
     explicit ModelInstance(ModelObject *object, const ModelInstance &other) :
-        m_transformation(other.m_transformation), print_volume_state(PVS_Inside), object(object)
-    {
-        assert(this->id().valid() && this->id() != other.id());
-        get_arrange_polygon(); // initialize the cache
-    }
+        m_transformation(other.m_transformation), print_volume_state(PVS_Inside), object(object) { assert(this->id().valid() && this->id() != other.id()); }
 
     explicit ModelInstance(ModelInstance &&rhs) = delete;
     ModelInstance& operator=(const ModelInstance &rhs) = delete;
@@ -647,12 +639,6 @@ private:
 	template<class Archive> void serialize(Archive &ar) {
 		ar(m_transformation, print_volume_state);
 	}
-    
-    // Warning! This object is not guarded against concurrency.
-    mutable struct ArrangeCache {
-        bool      valid = false;
-        ExPolygon poly;
-    } m_arrange_cache;
 };
 
 // The print bed content.