diff --git a/src/slic3r/GUI/3DBed.cpp b/src/slic3r/GUI/3DBed.cpp
index 3f29fd65b9..26b6c89908 100644
--- a/src/slic3r/GUI/3DBed.cpp
+++ b/src/slic3r/GUI/3DBed.cpp
@@ -45,8 +45,7 @@ bool init_model_from_poly(GLModel &model, const ExPolygon &poly, float z)
         return false;
 
     GLModel::Geometry init_data;
-    const GLModel::Geometry::EIndexType index_type = (triangles.size() < 65536) ? GLModel::Geometry::EIndexType::USHORT : GLModel::Geometry::EIndexType::UINT;
-    init_data.format = { GLModel::Geometry::EPrimitiveType::Triangles, GLModel::Geometry::EVertexLayout::P3T2, index_type };
+    init_data.format = { GLModel::Geometry::EPrimitiveType::Triangles, GLModel::Geometry::EVertexLayout::P3T2, GLModel::Geometry::index_type(triangles.size()) };
     init_data.reserve_vertices(triangles.size());
     init_data.reserve_indices(triangles.size() / 3);
 
@@ -71,7 +70,7 @@ bool init_model_from_poly(GLModel &model, const ExPolygon &poly, float z)
         init_data.add_vertex(p, (Vec2f)(v - min).cwiseProduct(inv_size).eval());
         ++vertices_counter;
         if (vertices_counter % 3 == 0) {
-            if (index_type == GLModel::Geometry::EIndexType::USHORT)
+            if (init_data.format.index_type == GLModel::Geometry::EIndexType::USHORT)
                 init_data.add_ushort_triangle((unsigned short)vertices_counter - 3, (unsigned short)vertices_counter - 2, (unsigned short)vertices_counter - 1);
             else
                 init_data.add_uint_triangle(vertices_counter - 3, vertices_counter - 2, vertices_counter - 1);
diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 6c53d00b97..c627837b4a 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -497,8 +497,7 @@ void GLCanvas3D::LayersEditing::render_profile(const Rect& bar_rect)
         m_profile.profile.reset();
 
         GLModel::Geometry init_data;
-        const GLModel::Geometry::EIndexType index_type = (m_layer_height_profile.size() / 2 < 65536) ? GLModel::Geometry::EIndexType::USHORT : GLModel::Geometry::EIndexType::UINT;
-        init_data.format = { GLModel::Geometry::EPrimitiveType::LineStrip, GLModel::Geometry::EVertexLayout::P2, index_type };
+        init_data.format = { GLModel::Geometry::EPrimitiveType::LineStrip, GLModel::Geometry::EVertexLayout::P2, GLModel::Geometry::index_type(m_layer_height_profile.size() / 2) };
         init_data.color = ColorRGBA::BLUE();
         init_data.reserve_vertices(m_layer_height_profile.size() / 2);
         init_data.reserve_indices(m_layer_height_profile.size() / 2);
@@ -507,7 +506,7 @@ void GLCanvas3D::LayersEditing::render_profile(const Rect& bar_rect)
         for (unsigned int i = 0; i < (unsigned int)m_layer_height_profile.size(); i += 2) {
             init_data.add_vertex(Vec2f(bar_rect.get_left() + float(m_layer_height_profile[i + 1]) * scale_x,
                                        bar_rect.get_bottom() + float(m_layer_height_profile[i]) * scale_y));
-            if (index_type == GLModel::Geometry::EIndexType::USHORT)
+            if (init_data.format.index_type == GLModel::Geometry::EIndexType::USHORT)
                 init_data.add_ushort_index((unsigned short)i / 2);
             else
                 init_data.add_uint_index(i / 2);
diff --git a/src/slic3r/GUI/GLModel.cpp b/src/slic3r/GUI/GLModel.cpp
index 64471f3f26..0cb7bfc96b 100644
--- a/src/slic3r/GUI/GLModel.cpp
+++ b/src/slic3r/GUI/GLModel.cpp
@@ -327,6 +327,11 @@ size_t GLModel::Geometry::index_stride_bytes(const Format& format)
     };
 }
 
+GLModel::Geometry::EIndexType GLModel::Geometry::index_type(size_t vertices_count)
+{
+    return (vertices_count < 65536) ? EIndexType::USHORT : EIndexType::UINT;
+}
+
 bool GLModel::Geometry::has_position(const Format& format)
 {
     switch (format.vertex_layout)
diff --git a/src/slic3r/GUI/GLModel.hpp b/src/slic3r/GUI/GLModel.hpp
index f1b9279fd6..98feaaad0a 100644
--- a/src/slic3r/GUI/GLModel.hpp
+++ b/src/slic3r/GUI/GLModel.hpp
@@ -63,11 +63,11 @@ namespace GUI {
             void reserve_vertices(size_t vertices_count);
             void reserve_indices(size_t indices_count);
 
-            void add_vertex(const Vec2f& position);
-            void add_vertex(const Vec2f& position, const Vec2f& tex_coord);
-            void add_vertex(const Vec3f& position);
-            void add_vertex(const Vec3f& position, const Vec2f& tex_coord);
-            void add_vertex(const Vec3f& position, const Vec3f& normal);
+            void add_vertex(const Vec2f& position);                          // EVertexLayout::P2
+            void add_vertex(const Vec2f& position, const Vec2f& tex_coord);  // EVertexLayout::P2T2
+            void add_vertex(const Vec3f& position);                          // EVertexLayout::P3
+            void add_vertex(const Vec3f& position, const Vec2f& tex_coord);  // EVertexLayout::P3T2
+            void add_vertex(const Vec3f& position, const Vec3f& normal);     // EVertexLayout::P3N3
 
             void add_ushort_index(unsigned short id);
             void add_uint_index(unsigned int id);
@@ -115,6 +115,8 @@ namespace GUI {
 
             static size_t index_stride_bytes(const Format& format);
 
+            static EIndexType index_type(size_t vertices_count);
+
             static bool has_position(const Format& format);
             static bool has_normal(const Format& format);
             static bool has_tex_coord(const Format& format);
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoFlatten.cpp b/src/slic3r/GUI/Gizmos/GLGizmoFlatten.cpp
index b67b18dfc3..71ce109794 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoFlatten.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoFlatten.cpp
@@ -337,14 +337,13 @@ void GLGizmoFlatten::update_planes()
     // the vertices in order, so triangulation is trivial.
     for (auto& plane : m_planes) {
         GLModel::Geometry init_data;
-        const GLModel::Geometry::EIndexType index_type = (plane.vertices.size() < 65536) ? GLModel::Geometry::EIndexType::USHORT : GLModel::Geometry::EIndexType::UINT;
-        init_data.format = { GLModel::Geometry::EPrimitiveType::TriangleFan, GLModel::Geometry::EVertexLayout::P3N3, index_type };
+        init_data.format = { GLModel::Geometry::EPrimitiveType::TriangleFan, GLModel::Geometry::EVertexLayout::P3N3, GLModel::Geometry::index_type(plane.vertices.size()) };
         init_data.reserve_vertices(plane.vertices.size());
         init_data.reserve_indices(plane.vertices.size());
         // vertices + indices
         for (size_t i = 0; i < plane.vertices.size(); ++i) {
             init_data.add_vertex((Vec3f)plane.vertices[i].cast<float>(), (Vec3f)plane.normal.cast<float>());
-            if (index_type == GLModel::Geometry::EIndexType::USHORT)
+            if (init_data.format.index_type == GLModel::Geometry::EIndexType::USHORT)
                 init_data.add_ushort_index((unsigned short)i);
             else
                 init_data.add_uint_index((unsigned int)i);
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp b/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp
index 4ef92a7ac2..6a6919b2be 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp
@@ -1661,8 +1661,7 @@ void TriangleSelectorGUI::update_paint_contour()
 
     GLModel::Geometry init_data;
     const std::vector<Vec2i> contour_edges = this->get_seed_fill_contour();
-    const GLModel::Geometry::EIndexType index_type = (2 * contour_edges.size() < 65536) ? GLModel::Geometry::EIndexType::USHORT : GLModel::Geometry::EIndexType::UINT;
-    init_data.format = { GLModel::Geometry::EPrimitiveType::Lines, GLModel::Geometry::EVertexLayout::P3, index_type };
+    init_data.format = { GLModel::Geometry::EPrimitiveType::Lines, GLModel::Geometry::EVertexLayout::P3, GLModel::Geometry::index_type(2 * contour_edges.size()) };
     init_data.reserve_vertices(2 * contour_edges.size());
     init_data.reserve_indices(2 * contour_edges.size());
     // vertices + indices
@@ -1671,7 +1670,7 @@ void TriangleSelectorGUI::update_paint_contour()
         init_data.add_vertex(m_vertices[edge(0)].v);
         init_data.add_vertex(m_vertices[edge(1)].v);
         vertices_count += 2;
-        if (index_type == GLModel::Geometry::EIndexType::USHORT)
+        if (init_data.format.index_type == GLModel::Geometry::EIndexType::USHORT)
             init_data.add_ushort_line((unsigned short)vertices_count - 2, (unsigned short)vertices_count - 1);
         else
             init_data.add_uint_line(vertices_count - 2, vertices_count - 1);
diff --git a/src/slic3r/GUI/MeshUtils.cpp b/src/slic3r/GUI/MeshUtils.cpp
index 64d9be0826..3cdf5b6368 100644
--- a/src/slic3r/GUI/MeshUtils.cpp
+++ b/src/slic3r/GUI/MeshUtils.cpp
@@ -205,8 +205,7 @@ void MeshClipper::recalculate_triangles()
     m_model.reset();
 
     GLModel::Geometry init_data;
-    const GLModel::Geometry::EIndexType index_type = (m_triangles2d.size() < 65536) ? GLModel::Geometry::EIndexType::USHORT : GLModel::Geometry::EIndexType::UINT;
-    init_data.format = { GLModel::Geometry::EPrimitiveType::Triangles, GLModel::Geometry::EVertexLayout::P3N3, index_type };
+    init_data.format = { GLModel::Geometry::EPrimitiveType::Triangles, GLModel::Geometry::EVertexLayout::P3N3, GLModel::Geometry::index_type(m_triangles2d.size()) };
     init_data.reserve_vertices(m_triangles2d.size());
     init_data.reserve_indices(m_triangles2d.size());
 
@@ -216,7 +215,7 @@ void MeshClipper::recalculate_triangles()
         init_data.add_vertex((Vec3f)(tr * Vec3d((*(it + 1)).x(), (*(it + 1)).y(), height_mesh)).cast<float>(), (Vec3f)up.cast<float>());
         init_data.add_vertex((Vec3f)(tr * Vec3d((*(it + 2)).x(), (*(it + 2)).y(), height_mesh)).cast<float>(), (Vec3f)up.cast<float>());
         const size_t idx = it - m_triangles2d.cbegin();
-        if (index_type == GLModel::Geometry::EIndexType::USHORT)
+        if (init_data.format.index_type == GLModel::Geometry::EIndexType::USHORT)
             init_data.add_ushort_triangle((unsigned short)idx, (unsigned short)idx + 1, (unsigned short)idx + 2);
         else
             init_data.add_uint_triangle((unsigned int)idx, (unsigned int)idx + 1, (unsigned int)idx + 2);
diff --git a/src/slic3r/GUI/PartPlate.cpp b/src/slic3r/GUI/PartPlate.cpp
index 27e819b45a..ee7f3bc47e 100644
--- a/src/slic3r/GUI/PartPlate.cpp
+++ b/src/slic3r/GUI/PartPlate.cpp
@@ -351,8 +351,7 @@ static bool init_model_from_lines(GLModel &model, const Lines &lines, float z)
 {
 
     GLModel::Geometry init_data;
-    const GLModel::Geometry::EIndexType index_type = (lines.size() < 65536 / 2) ? GLModel::Geometry::EIndexType::USHORT : GLModel::Geometry::EIndexType::UINT;
-    init_data.format = { GLModel::Geometry::EPrimitiveType::Lines, GLModel::Geometry::EVertexLayout::P3, index_type };
+    init_data.format = { GLModel::Geometry::EPrimitiveType::Lines, GLModel::Geometry::EVertexLayout::P3, GLModel::Geometry::index_type(2 * lines.size()) };
     init_data.reserve_vertices(2 * lines.size());
     init_data.reserve_indices(2 * lines.size());
 
@@ -360,7 +359,7 @@ static bool init_model_from_lines(GLModel &model, const Lines &lines, float z)
         init_data.add_vertex(Vec3f(unscale<float>(l.a.x()), unscale<float>(l.a.y()), z));
         init_data.add_vertex(Vec3f(unscale<float>(l.b.x()), unscale<float>(l.b.y()), z));
         const unsigned int vertices_counter = (unsigned int)init_data.vertices_count();
-        if (index_type == GLModel::Geometry::EIndexType::USHORT)
+        if (init_data.format.index_type == GLModel::Geometry::EIndexType::USHORT)
             init_data.add_ushort_line((unsigned short)vertices_counter - 2, (unsigned short)vertices_counter - 1);
         else
             init_data.add_uint_line(vertices_counter - 2, vertices_counter - 1);
@@ -375,8 +374,7 @@ static bool init_model_from_lines(GLModel &model, const Lines3 &lines)
 {
 
     GLModel::Geometry init_data;
-    const GLModel::Geometry::EIndexType index_type = (lines.size() < 65536 / 2) ? GLModel::Geometry::EIndexType::USHORT : GLModel::Geometry::EIndexType::UINT;
-    init_data.format = {GLModel::Geometry::EPrimitiveType::Lines, GLModel::Geometry::EVertexLayout::P3, index_type};
+    init_data.format = {GLModel::Geometry::EPrimitiveType::Lines, GLModel::Geometry::EVertexLayout::P3, GLModel::Geometry::index_type(2 * lines.size())};
     init_data.reserve_vertices(2 * lines.size());
     init_data.reserve_indices(2 * lines.size());
 
@@ -384,7 +382,7 @@ static bool init_model_from_lines(GLModel &model, const Lines3 &lines)
         init_data.add_vertex(Vec3f(unscale<float>(l.a.x()), unscale<float>(l.a.y()), unscale<float>(l.a.z())));
         init_data.add_vertex(Vec3f(unscale<float>(l.b.x()), unscale<float>(l.b.y()), unscale<float>(l.b.z())));
         const unsigned int vertices_counter = (unsigned int) init_data.vertices_count();
-        if (index_type == GLModel::Geometry::EIndexType::USHORT)
+        if (init_data.format.index_type == GLModel::Geometry::EIndexType::USHORT)
             init_data.add_ushort_line((unsigned short) vertices_counter - 2, (unsigned short) vertices_counter - 1);
         else
             init_data.add_uint_line(vertices_counter - 2, vertices_counter - 1);