diff --git a/src/libslic3r/TriangleMesh.cpp b/src/libslic3r/TriangleMesh.cpp
index 4a1039b56..a92e55194 100644
--- a/src/libslic3r/TriangleMesh.cpp
+++ b/src/libslic3r/TriangleMesh.cpp
@@ -899,6 +899,39 @@ void its_shrink_to_fit(indexed_triangle_set &its)
     its.vertices.shrink_to_fit();
 }
 
+template<typename TransformVertex>
+Polygon its_convex_hull_2d_above(const indexed_triangle_set &its, const TransformVertex &transform_fn, const float z)
+{
+    Points all_pts;
+    for (const stl_triangle_vertex_indices &tri : its.indices) {
+        const Vec3f pts[3] = { transform_fn(its.vertices[tri(0)]), transform_fn(its.vertices[tri(1)]), transform_fn(its.vertices[tri(2)]) };
+        int iprev = 3;
+        for (int iedge = 0; iedge < 3; ++ iedge) {
+            const Vec3f &p1 = pts[iprev];
+            const Vec3f &p2 = pts[iedge];
+            if ((p1.z() < z && p2.z() > z) || (p2.z() < z && p1.z() > z)) {
+                // Edge crosses the z plane. Calculate intersection point with the plane.
+                float t = z / (p2.z() - p1.z());
+                all_pts.emplace_back(scaled<coord_t>(p1.x() + (p2.x() - p1.x()) * t), scaled<coord_t>(p2.x() + (p2.y() - p2.y()) * t));
+            }
+            if (p2.z() > z)
+                all_pts.emplace_back(scaled<coord_t>(p2.x()), scaled<coord_t>(p2.y()));
+            iprev = iedge;
+        }
+    }
+    return Geometry::convex_hull(std::move(all_pts));
+}
+
+Polygon its_convex_hull_2d_above(const indexed_triangle_set &its, const Matrix3f &m, const float z)
+{
+    return its_convex_hull_2d_above(its, [m](const Vec3f &p){ return m * p; }, z);
+}
+
+Polygon its_convex_hull_2d_above(const indexed_triangle_set &its, const Transform3f &t, const float z)
+{
+    return its_convex_hull_2d_above(its, [t](const Vec3f &p){ return t * p; }, z);
+}
+
 // Generate the vertex list for a cube solid of arbitrary size in X/Y/Z.
 TriangleMesh make_cube(double x, double y, double z) 
 {
diff --git a/src/libslic3r/TriangleMesh.hpp b/src/libslic3r/TriangleMesh.hpp
index 5d3c15ec1..59a8715a0 100644
--- a/src/libslic3r/TriangleMesh.hpp
+++ b/src/libslic3r/TriangleMesh.hpp
@@ -113,6 +113,9 @@ int its_compactify_vertices(indexed_triangle_set &its, bool shrink_to_fit = true
 // Shrink the vectors of its.vertices and its.faces to a minimum size by reallocating the two vectors.
 void its_shrink_to_fit(indexed_triangle_set &its);
 
+Polygon its_convex_hull_2d_above(const indexed_triangle_set &its, const Matrix3f &m, const float z);
+Polygon its_convex_hull_2d_above(const indexed_triangle_set &its, const Transform3f &t, const float z);
+
 TriangleMesh make_cube(double x, double y, double z);
 
 // Generate a TriangleMesh of a cylinder