diff --git a/src/slic3r/GUI/3DScene.cpp b/src/slic3r/GUI/3DScene.cpp
index c483f0ec3..fe0cd9ffb 100644
--- a/src/slic3r/GUI/3DScene.cpp
+++ b/src/slic3r/GUI/3DScene.cpp
@@ -74,13 +74,13 @@ void GLIndexedVertexArray::load_mesh_full_shading(const TriangleMesh &mesh)
     }
 }
 
-void GLIndexedVertexArray::finalize_geometry()
+void GLIndexedVertexArray::finalize_geometry() const
 {
     assert(this->vertices_and_normals_interleaved_VBO_id == 0);
     assert(this->triangle_indices_VBO_id == 0);
     assert(this->quad_indices_VBO_id == 0);
 
-    this->setup_sizes();
+    this->shrink_to_fit();
 
     if (! empty()) {
         glsafe(::glGenBuffers(1, &this->vertices_and_normals_interleaved_VBO_id));
@@ -103,8 +103,6 @@ void GLIndexedVertexArray::finalize_geometry()
         glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0));
         this->quad_indices.clear();
     }
-
-    this->shrink_to_fit();
 }
 
 void GLIndexedVertexArray::release_geometry()
@@ -122,89 +120,78 @@ void GLIndexedVertexArray::release_geometry()
         this->quad_indices_VBO_id = 0;
     }
     this->clear();
-    this->shrink_to_fit();
 }
 
 void GLIndexedVertexArray::render() const
 {
-    if (this->vertices_and_normals_interleaved_VBO_id) {
-        glsafe(::glBindBuffer(GL_ARRAY_BUFFER, this->vertices_and_normals_interleaved_VBO_id));
-        glsafe(::glVertexPointer(3, GL_FLOAT, 6 * sizeof(float), (const void*)(3 * sizeof(float))));
-        glsafe(::glNormalPointer(GL_FLOAT, 6 * sizeof(float), nullptr));
-    } else {
-        glsafe(::glVertexPointer(3, GL_FLOAT, 6 * sizeof(float), this->vertices_and_normals_interleaved.data() + 3));
-        glsafe(::glNormalPointer(GL_FLOAT, 6 * sizeof(float), this->vertices_and_normals_interleaved.data()));
+    if (this->vertices_and_normals_interleaved_VBO_id == 0)
+    {
+        // sends data to gpu, if not done yet
+        finalize_geometry();
+        if (this->vertices_and_normals_interleaved_VBO_id == 0)
+            return;
     }
+
+    glsafe(::glBindBuffer(GL_ARRAY_BUFFER, this->vertices_and_normals_interleaved_VBO_id));
+    glsafe(::glVertexPointer(3, GL_FLOAT, 6 * sizeof(float), (const void*)(3 * sizeof(float))));
+    glsafe(::glNormalPointer(GL_FLOAT, 6 * sizeof(float), nullptr));
+
     glsafe(::glEnableClientState(GL_VERTEX_ARRAY));
     glsafe(::glEnableClientState(GL_NORMAL_ARRAY));
 
-    if (this->indexed()) {
-        if (this->vertices_and_normals_interleaved_VBO_id) {
-            // Render using the Vertex Buffer Objects.
-            if (this->triangle_indices_size > 0) {
-                glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, this->triangle_indices_VBO_id));
-                glsafe(::glDrawElements(GL_TRIANGLES, GLsizei(this->triangle_indices_size), GL_UNSIGNED_INT, nullptr));
-            }
-            if (this->quad_indices_size > 0) {
-                glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, this->quad_indices_VBO_id));
-                glsafe(::glDrawElements(GL_QUADS, GLsizei(this->quad_indices_size), GL_UNSIGNED_INT, nullptr));
-            }
-            glsafe(glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0));
-        } else {
-            // Render in an immediate mode.
-            if (! this->triangle_indices.empty())
-                glsafe(::glDrawElements(GL_TRIANGLES, GLsizei(this->triangle_indices_size), GL_UNSIGNED_INT, this->triangle_indices.data()));
-            if (! this->quad_indices.empty())
-                glsafe(::glDrawElements(GL_QUADS, GLsizei(this->quad_indices_size), GL_UNSIGNED_INT, this->quad_indices.data()));
-        }
-    } else
-        glsafe(::glDrawArrays(GL_TRIANGLES, 0, GLsizei(this->vertices_and_normals_interleaved_size / 6)));
-
-    if (this->vertices_and_normals_interleaved_VBO_id)
-        glsafe(::glBindBuffer(GL_ARRAY_BUFFER, 0));
-    glsafe(::glDisableClientState(GL_VERTEX_ARRAY));
-    glsafe(::glDisableClientState(GL_NORMAL_ARRAY));
-}
-
-void GLIndexedVertexArray::render(
-    const std::pair<size_t, size_t> &tverts_range,
-    const std::pair<size_t, size_t> &qverts_range) const 
-{
-    assert(this->indexed());
-    if (! this->indexed())
-        return;
-
-    if (this->vertices_and_normals_interleaved_VBO_id) {
-        // Render using the Vertex Buffer Objects.
-        glsafe(::glBindBuffer(GL_ARRAY_BUFFER, this->vertices_and_normals_interleaved_VBO_id));
-        glsafe(::glVertexPointer(3, GL_FLOAT, 6 * sizeof(float), (const void*)(3 * sizeof(float))));
-        glsafe(::glNormalPointer(GL_FLOAT, 6 * sizeof(float), nullptr));
-        glsafe(::glEnableClientState(GL_VERTEX_ARRAY));
-        glsafe(::glEnableClientState(GL_NORMAL_ARRAY));
-        if (this->triangle_indices_size > 0) {
-            glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, this->triangle_indices_VBO_id));
-            glsafe(::glDrawElements(GL_TRIANGLES, GLsizei(std::min(this->triangle_indices_size, tverts_range.second - tverts_range.first)), GL_UNSIGNED_INT, (const void*)(tverts_range.first * 4)));
-        }
-        if (this->quad_indices_size > 0) {
-            glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, this->quad_indices_VBO_id));
-            glsafe(::glDrawElements(GL_QUADS, GLsizei(std::min(this->quad_indices_size, qverts_range.second - qverts_range.first)), GL_UNSIGNED_INT, (const void*)(qverts_range.first * 4)));
-        }
-        glsafe(::glBindBuffer(GL_ARRAY_BUFFER, 0));
-        glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0));
-    } else {
-        // Render in an immediate mode.
-        glsafe(::glVertexPointer(3, GL_FLOAT, 6 * sizeof(float), this->vertices_and_normals_interleaved.data() + 3));
-        glsafe(::glNormalPointer(GL_FLOAT, 6 * sizeof(float), this->vertices_and_normals_interleaved.data()));
-        glsafe(::glEnableClientState(GL_VERTEX_ARRAY));
-        glsafe(::glEnableClientState(GL_NORMAL_ARRAY));
-        if (! this->triangle_indices.empty())
-            glsafe(::glDrawElements(GL_TRIANGLES, GLsizei(std::min(this->triangle_indices_size, tverts_range.second - tverts_range.first)), GL_UNSIGNED_INT, (const void*)(this->triangle_indices.data() + tverts_range.first)));
-        if (! this->quad_indices.empty())
-            glsafe(::glDrawElements(GL_QUADS, GLsizei(std::min(this->quad_indices_size, qverts_range.second - qverts_range.first)), GL_UNSIGNED_INT, (const void*)(this->quad_indices.data() + qverts_range.first)));
+    // Render using the Vertex Buffer Objects.
+    if (this->triangle_indices_size > 0) {
+        glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, this->triangle_indices_VBO_id));
+        glsafe(::glDrawElements(GL_TRIANGLES, GLsizei(this->triangle_indices_size), GL_UNSIGNED_INT, nullptr));
+        glsafe(glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0));
+    }
+    if (this->quad_indices_size > 0) {
+        glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, this->quad_indices_VBO_id));
+        glsafe(::glDrawElements(GL_QUADS, GLsizei(this->quad_indices_size), GL_UNSIGNED_INT, nullptr));
+        glsafe(glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0));
     }
 
     glsafe(::glDisableClientState(GL_VERTEX_ARRAY));
     glsafe(::glDisableClientState(GL_NORMAL_ARRAY));
+
+    glsafe(::glBindBuffer(GL_ARRAY_BUFFER, 0));
+}
+
+void GLIndexedVertexArray::render(
+    const std::pair<size_t, size_t>& tverts_range,
+    const std::pair<size_t, size_t>& qverts_range) const
+{
+    if (this->vertices_and_normals_interleaved_VBO_id == 0)
+    {
+        // sends data to gpu, if not done yet
+        finalize_geometry();
+        if (this->vertices_and_normals_interleaved_VBO_id == 0)
+            return;
+    }
+
+    // Render using the Vertex Buffer Objects.
+    glsafe(::glBindBuffer(GL_ARRAY_BUFFER, this->vertices_and_normals_interleaved_VBO_id));
+    glsafe(::glVertexPointer(3, GL_FLOAT, 6 * sizeof(float), (const void*)(3 * sizeof(float))));
+    glsafe(::glNormalPointer(GL_FLOAT, 6 * sizeof(float), nullptr));
+
+    glsafe(::glEnableClientState(GL_VERTEX_ARRAY));
+    glsafe(::glEnableClientState(GL_NORMAL_ARRAY));
+
+    if (this->triangle_indices_size > 0) {
+        glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, this->triangle_indices_VBO_id));
+        glsafe(::glDrawElements(GL_TRIANGLES, GLsizei(std::min(this->triangle_indices_size, tverts_range.second - tverts_range.first)), GL_UNSIGNED_INT, (const void*)(tverts_range.first * 4)));
+        glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0));
+    }
+    if (this->quad_indices_size > 0) {
+        glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, this->quad_indices_VBO_id));
+        glsafe(::glDrawElements(GL_QUADS, GLsizei(std::min(this->quad_indices_size, qverts_range.second - qverts_range.first)), GL_UNSIGNED_INT, (const void*)(qverts_range.first * 4)));
+        glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0));
+    }
+
+    glsafe(::glDisableClientState(GL_VERTEX_ARRAY));
+    glsafe(::glDisableClientState(GL_NORMAL_ARRAY));
+    
+    glsafe(::glBindBuffer(GL_ARRAY_BUFFER, 0));
 }
 
 const float GLVolume::SELECTED_COLOR[4] = { 0.0f, 1.0f, 0.0f, 1.0f };
@@ -357,9 +344,9 @@ BoundingBoxf3 GLVolume::transformed_convex_hull_bounding_box(const Transform3d &
 
 void GLVolume::set_range(double min_z, double max_z)
 {
-    this->qverts_range.first  = 0;
+    this->qverts_range.first = 0;
     this->qverts_range.second = this->indexed_vertex_array.quad_indices_size;
-    this->tverts_range.first  = 0;
+    this->tverts_range.first = 0;
     this->tverts_range.second = this->indexed_vertex_array.triangle_indices_size;
     if (! this->print_zs.empty()) {
         // The Z layer range is specified.
@@ -399,12 +386,10 @@ void GLVolume::render() const
         glFrontFace(GL_CW);
     glsafe(::glCullFace(GL_BACK));
     glsafe(::glPushMatrix());
-
     glsafe(::glMultMatrixd(world_matrix().data()));
-    if (this->indexed_vertex_array.indexed())
-        this->indexed_vertex_array.render(this->tverts_range, this->qverts_range);
-    else
-        this->indexed_vertex_array.render();
+
+    this->indexed_vertex_array.render(this->tverts_range, this->qverts_range);
+
     glsafe(::glPopMatrix());
     if (this->is_left_handed())
         glFrontFace(GL_CCW);
@@ -412,45 +397,6 @@ void GLVolume::render() const
 
 void GLVolume::render(int color_id, int detection_id, int worldmatrix_id) const
 {
-    if (!is_active)
-        return;
-
-    if (!indexed_vertex_array.vertices_and_normals_interleaved_VBO_id)
-        return;
-
-    GLsizei n_triangles = GLsizei(std::min(indexed_vertex_array.triangle_indices_size, tverts_range.second - tverts_range.first));
-    GLsizei n_quads = GLsizei(std::min(indexed_vertex_array.quad_indices_size, qverts_range.second - qverts_range.first));
-    if (n_triangles + n_quads == 0)
-    {
-        glsafe(::glDisableClientState(GL_VERTEX_ARRAY));
-        glsafe(::glDisableClientState(GL_NORMAL_ARRAY));
-
-        if (color_id >= 0)
-        {
-            float color[4];
-            ::memcpy((void*)color, (const void*)render_color, 4 * sizeof(float));
-            glsafe(::glUniform4fv(color_id, 1, (const GLfloat*)color));
-        }
-        else
-            glsafe(::glColor4fv(render_color));
-
-        if (detection_id != -1)
-            glsafe(::glUniform1i(detection_id, shader_outside_printer_detection_enabled ? 1 : 0));
-
-        if (worldmatrix_id != -1)
-            glsafe(::glUniformMatrix4fv(worldmatrix_id, 1, GL_FALSE, (const GLfloat*)world_matrix().cast<float>().data()));
-
-        render();
-
-        glsafe(::glEnableClientState(GL_VERTEX_ARRAY));
-        glsafe(::glEnableClientState(GL_NORMAL_ARRAY));
-
-        return;
-    }
-
-    if (this->is_left_handed())
-        glFrontFace(GL_CW);
-
     if (color_id >= 0)
         glsafe(::glUniform4fv(color_id, 1, (const GLfloat*)render_color));
     else
@@ -462,29 +408,7 @@ void GLVolume::render(int color_id, int detection_id, int worldmatrix_id) const
     if (worldmatrix_id != -1)
         glsafe(::glUniformMatrix4fv(worldmatrix_id, 1, GL_FALSE, (const GLfloat*)world_matrix().cast<float>().data()));
 
-    glsafe(::glBindBuffer(GL_ARRAY_BUFFER, indexed_vertex_array.vertices_and_normals_interleaved_VBO_id));
-    glsafe(::glVertexPointer(3, GL_FLOAT, 6 * sizeof(float), (const void*)(3 * sizeof(float))));
-    glsafe(::glNormalPointer(GL_FLOAT, 6 * sizeof(float), nullptr));
-
-    glsafe(::glPushMatrix());
-
-    glsafe(::glMultMatrixd(world_matrix().data()));
-
-    if (n_triangles > 0)
-    {
-        glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexed_vertex_array.triangle_indices_VBO_id));
-        glsafe(::glDrawElements(GL_TRIANGLES, n_triangles, GL_UNSIGNED_INT, (const void*)(tverts_range.first * 4)));
-    }
-    if (n_quads > 0)
-    {
-        glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexed_vertex_array.quad_indices_VBO_id));
-        glsafe(::glDrawElements(GL_QUADS, n_quads, GL_UNSIGNED_INT, (const void*)(qverts_range.first * 4)));
-    }
-
-    glsafe(::glPopMatrix());
-
-    if (this->is_left_handed())
-        glFrontFace(GL_CCW);
+    render();
 }
 
 bool GLVolume::is_sla_support() const { return this->composite_id.volume_id == -int(slaposSupportTree); }
@@ -531,8 +455,6 @@ int GLVolumeCollection::load_object_volume(
     GLVolume& v = *this->volumes.back();
     v.set_color_from_model_volume(model_volume);
     v.indexed_vertex_array.load_mesh(mesh);
-
-    v.indexed_vertex_array.finalize_geometry();
     v.composite_id = GLVolume::CompositeID(obj_idx, volume_idx, instance_idx);
     if (model_volume->is_model_part())
     {
@@ -573,7 +495,6 @@ void GLVolumeCollection::load_object_auxiliary(
         this->volumes.emplace_back(new GLVolume((milestone == slaposBasePool) ? GLVolume::SLA_PAD_COLOR : GLVolume::SLA_SUPPORT_COLOR));
         GLVolume& v = *this->volumes.back();
         v.indexed_vertex_array.load_mesh(mesh);
-        v.indexed_vertex_array.finalize_geometry();
         v.composite_id = GLVolume::CompositeID(obj_idx, -int(milestone), (int)instance_idx.first);
         v.geometry_id = std::pair<size_t, size_t>(timestamp, model_instance.id().id);
         // Create a copy of the convex hull mesh for each instance. Use a move operator on the last instance.
@@ -645,8 +566,6 @@ int GLVolumeCollection::load_wipe_tower_preview(
     v.indexed_vertex_array.load_mesh(mesh);
     v.set_volume_offset(Vec3d(pos_x, pos_y, 0.0));
     v.set_volume_rotation(Vec3d(0., 0., (M_PI / 180.) * rotation_angle));
-
-    v.indexed_vertex_array.finalize_geometry();
     v.composite_id = GLVolume::CompositeID(obj_idx, 0, 0);
     v.geometry_id.first = 0;
     v.geometry_id.second = wipe_tower_instance_id().id;
@@ -1576,7 +1495,9 @@ void GLModel::set_scale(const Vec3d& scale)
 
 void GLModel::reset()
 {
-    m_volume.release_geometry();
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+//    m_volume.release_geometry();
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
     m_filename = "";
 }
 
@@ -1659,7 +1580,6 @@ bool GLArrow::on_init()
     triangles.emplace_back(7, 13, 6);
 
     m_volume.indexed_vertex_array.load_mesh(TriangleMesh(vertices, triangles));
-    m_volume.finalize_geometry();
     return true;
 }
 
@@ -1773,7 +1693,6 @@ bool GLCurvedArrow::on_init()
     triangles.emplace_back(vertices_per_level, 2 * vertices_per_level + 1, vertices_per_level + 1);
 
     m_volume.indexed_vertex_array.load_mesh(TriangleMesh(vertices, triangles));
-    m_volume.finalize_geometry();
     return true;
 }
 
@@ -1810,8 +1729,6 @@ bool GLBed::on_init_from_file(const std::string& filename)
     float color[4] = { 0.235f, 0.235f, 0.235f, 1.0f };
     set_color(color, 4);
 
-    m_volume.finalize_geometry();
-
     return true;
 }
 
diff --git a/src/slic3r/GUI/3DScene.hpp b/src/slic3r/GUI/3DScene.hpp
index f3db00462..bb629a1d8 100644
--- a/src/slic3r/GUI/3DScene.hpp
+++ b/src/slic3r/GUI/3DScene.hpp
@@ -56,7 +56,7 @@ public:
         vertices_and_normals_interleaved_VBO_id(0),
         triangle_indices_VBO_id(0),
         quad_indices_VBO_id(0)
-        { this->setup_sizes(); }
+        {}
     GLIndexedVertexArray(const GLIndexedVertexArray &rhs) :
         vertices_and_normals_interleaved(rhs.vertices_and_normals_interleaved),
         triangle_indices(rhs.triangle_indices),
@@ -64,7 +64,7 @@ public:
         vertices_and_normals_interleaved_VBO_id(0),
         triangle_indices_VBO_id(0),
         quad_indices_VBO_id(0)
-        { this->setup_sizes(); }
+        {}
     GLIndexedVertexArray(GLIndexedVertexArray &&rhs) :
         vertices_and_normals_interleaved(std::move(rhs.vertices_and_normals_interleaved)),
         triangle_indices(std::move(rhs.triangle_indices)),
@@ -72,7 +72,11 @@ public:
         vertices_and_normals_interleaved_VBO_id(0),
         triangle_indices_VBO_id(0),
         quad_indices_VBO_id(0)
-        { this->setup_sizes(); }
+        {}
+
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+    ~GLIndexedVertexArray() { release_geometry(); }
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 
     GLIndexedVertexArray& operator=(const GLIndexedVertexArray &rhs)
     {
@@ -83,7 +87,9 @@ public:
         this->triangle_indices                 = rhs.triangle_indices;
         this->quad_indices                     = rhs.quad_indices;
         this->m_bounding_box                   = rhs.m_bounding_box;
-        this->setup_sizes();
+        vertices_and_normals_interleaved_size  = rhs.vertices_and_normals_interleaved_size;
+        triangle_indices_size                  = rhs.triangle_indices_size;
+        quad_indices_size                      = rhs.quad_indices_size;
         return *this;
     }
 
@@ -96,26 +102,28 @@ public:
         this->triangle_indices                 = std::move(rhs.triangle_indices);
         this->quad_indices                     = std::move(rhs.quad_indices);
         this->m_bounding_box                   = std::move(rhs.m_bounding_box);
-        this->setup_sizes();
+        vertices_and_normals_interleaved_size  = rhs.vertices_and_normals_interleaved_size;
+        triangle_indices_size                  = rhs.triangle_indices_size;
+        quad_indices_size                      = rhs.quad_indices_size;
         return *this;
     }
 
     // Vertices and their normals, interleaved to be used by void glInterleavedArrays(GL_N3F_V3F, 0, x)
-    std::vector<float> vertices_and_normals_interleaved;
-    std::vector<int>   triangle_indices;
-    std::vector<int>   quad_indices;
+    mutable std::vector<float> vertices_and_normals_interleaved;
+    mutable std::vector<int>   triangle_indices;
+    mutable std::vector<int>   quad_indices;
 
     // When the geometry data is loaded into the graphics card as Vertex Buffer Objects,
     // the above mentioned std::vectors are cleared and the following variables keep their original length.
-    size_t             vertices_and_normals_interleaved_size;
-    size_t             triangle_indices_size;
-    size_t             quad_indices_size;
+    size_t vertices_and_normals_interleaved_size{ 0 };
+    size_t triangle_indices_size{ 0 };
+    size_t quad_indices_size{ 0 };
 
     // IDs of the Vertex Array Objects, into which the geometry has been loaded.
     // Zero if the VBOs are not sent to GPU yet.
-    unsigned int       vertices_and_normals_interleaved_VBO_id;
-    unsigned int       triangle_indices_VBO_id;
-    unsigned int       quad_indices_VBO_id;
+    mutable unsigned int       vertices_and_normals_interleaved_VBO_id{ 0 };
+    mutable unsigned int       triangle_indices_VBO_id{ 0 };
+    mutable unsigned int       quad_indices_VBO_id{ 0 };
 
     void load_mesh_full_shading(const TriangleMesh &mesh);
     void load_mesh(const TriangleMesh& mesh) { this->load_mesh_full_shading(mesh); }
@@ -129,6 +137,10 @@ public:
     }
 
     inline void push_geometry(float x, float y, float z, float nx, float ny, float nz) {
+        assert(this->vertices_and_normals_interleaved_VBO_id == 0);
+        if (this->vertices_and_normals_interleaved_VBO_id != 0)
+            return;
+
         if (this->vertices_and_normals_interleaved.size() + 6 > this->vertices_and_normals_interleaved.capacity())
             this->vertices_and_normals_interleaved.reserve(next_highest_power_of_2(this->vertices_and_normals_interleaved.size() + 6));
         this->vertices_and_normals_interleaved.push_back(nx);
@@ -138,6 +150,7 @@ public:
         this->vertices_and_normals_interleaved.push_back(y);
         this->vertices_and_normals_interleaved.push_back(z);
 
+        this->vertices_and_normals_interleaved_size = this->vertices_and_normals_interleaved.size();
         m_bounding_box.merge(Vec3f(x, y, z).cast<double>());
     };
 
@@ -150,50 +163,57 @@ public:
     }
 
     inline void push_triangle(int idx1, int idx2, int idx3) {
+        assert(this->vertices_and_normals_interleaved_VBO_id == 0);
+        if (this->vertices_and_normals_interleaved_VBO_id != 0)
+            return;
+
         if (this->triangle_indices.size() + 3 > this->vertices_and_normals_interleaved.capacity())
             this->triangle_indices.reserve(next_highest_power_of_2(this->triangle_indices.size() + 3));
         this->triangle_indices.push_back(idx1);
         this->triangle_indices.push_back(idx2);
         this->triangle_indices.push_back(idx3);
+        this->triangle_indices_size = this->triangle_indices.size();
     };
 
     inline void push_quad(int idx1, int idx2, int idx3, int idx4) {
+        assert(this->vertices_and_normals_interleaved_VBO_id == 0);
+        if (this->vertices_and_normals_interleaved_VBO_id != 0)
+            return;
+
         if (this->quad_indices.size() + 4 > this->vertices_and_normals_interleaved.capacity())
             this->quad_indices.reserve(next_highest_power_of_2(this->quad_indices.size() + 4));
         this->quad_indices.push_back(idx1);
         this->quad_indices.push_back(idx2);
         this->quad_indices.push_back(idx3);
         this->quad_indices.push_back(idx4);
+        this->quad_indices_size = this->quad_indices.size();
     };
 
     // Finalize the initialization of the geometry & indices,
     // upload the geometry and indices to OpenGL VBO objects
     // and shrink the allocated data, possibly relasing it if it has been loaded into the VBOs.
-    void finalize_geometry();
+    void finalize_geometry() const;
     // Release the geometry data, release OpenGL VBOs.
     void release_geometry();
 
     void render() const;
-    void render(const std::pair<size_t, size_t> &tverts_range, const std::pair<size_t, size_t> &qverts_range) const;
+    void render(const std::pair<size_t, size_t>& tverts_range, const std::pair<size_t, size_t>& qverts_range) const;
 
     // Is there any geometry data stored?
     bool empty() const { return vertices_and_normals_interleaved_size == 0; }
 
-    // Is this object indexed, or is it just a set of triangles?
-    bool indexed() const { return ! this->empty() && this->triangle_indices_size + this->quad_indices_size > 0; }
-
     void clear() {
         this->vertices_and_normals_interleaved.clear();
         this->triangle_indices.clear();
         this->quad_indices.clear();
         this->m_bounding_box.reset();
-        this->setup_sizes();
+        vertices_and_normals_interleaved_size = 0;
+        triangle_indices_size = 0;
+        quad_indices_size = 0;
     }
 
     // Shrink the internal storage to tighly fit the data stored.
-    void shrink_to_fit() { 
-        if (! this->has_VBOs())
-            this->setup_sizes();
+    void shrink_to_fit() const {
         this->vertices_and_normals_interleaved.shrink_to_fit();
         this->triangle_indices.shrink_to_fit();
         this->quad_indices.shrink_to_fit();
@@ -203,12 +223,6 @@ public:
 
 private:
     BoundingBoxf3 m_bounding_box;
-
-    inline void setup_sizes() {
-        vertices_and_normals_interleaved_size = this->vertices_and_normals_interleaved.size();
-        triangle_indices_size                 = this->triangle_indices.size();
-        quad_indices_size                     = this->quad_indices.size();
-    }
 };
 
 class GLVolume {
@@ -400,9 +414,9 @@ public:
     const BoundingBoxf3& transformed_convex_hull_bounding_box() const;
 
     bool                empty() const { return this->indexed_vertex_array.empty(); }
-    bool                indexed() const { return this->indexed_vertex_array.indexed(); }
 
     void                set_range(coordf_t low, coordf_t high);
+
     void                render() const;
     void                render(int color_id, int detection_id, int worldmatrix_id) const;
 
diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 5655390ec..dbca770d6 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -524,7 +524,7 @@ void GLCanvas3D::LayersEditing::render_volumes(const GLCanvas3D& canvas, const G
         glsafe(::glTexImage2D(GL_TEXTURE_2D, 1, GL_RGBA, half_w, half_h, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0));
         glsafe(::glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, m_layers_texture.data.data()));
         glsafe(::glTexSubImage2D(GL_TEXTURE_2D, 1, 0, 0, half_w, half_h, GL_RGBA, GL_UNSIGNED_BYTE, m_layers_texture.data.data() + m_layers_texture.width * m_layers_texture.height * 4));
-        for (const GLVolume *glvolume : volumes.volumes) {
+        for (const GLVolume* glvolume : volumes.volumes) {
             // Render the object using the layer editing shader and texture.
             if (! glvolume->is_active || glvolume->composite_id.object_id != this->last_object_id || glvolume->is_modifier)
                 continue;
@@ -543,8 +543,8 @@ void GLCanvas3D::LayersEditing::render_volumes(const GLCanvas3D& canvas, const G
     {
         // Something went wrong. Just render the object.
         assert(false);
-		for (const GLVolume *glvolume : volumes.volumes) {
-			// Render the object using the layer editing shader and texture.
+        for (const GLVolume* glvolume : volumes.volumes) {
+            // Render the object using the layer editing shader and texture.
 			if (!glvolume->is_active || glvolume->composite_id.object_id != this->last_object_id || glvolume->is_modifier)
 				continue;
             glsafe(::glUniformMatrix4fv(world_matrix_id, 1, GL_FALSE, (const GLfloat*)glvolume->world_matrix().cast<float>().data()));
@@ -1314,10 +1314,10 @@ bool GLCanvas3D::init()
         return false;
     }
 
-    // on linux the gl context is not valid until the canvas is not shown on screen
-    // we defer the geometry finalization of volumes until the first call to render()
-    if (!m_volumes.empty())
-        m_volumes.finalize_geometry();
+//    // on linux the gl context is not valid until the canvas is not shown on screen
+//    // we defer the geometry finalization of volumes until the first call to render()
+//    if (!m_volumes.empty())
+//        m_volumes.finalize_geometry();
 
     if (m_gizmos.is_enabled() && !m_gizmos.init(*this))
         std::cout << "Unable to initialize gizmos: please, check that all the required textures are available" << std::endl;
@@ -1355,7 +1355,9 @@ void GLCanvas3D::reset_volumes()
     if (!m_volumes.empty())
     {
         m_selection.clear();
-        m_volumes.release_geometry();
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+//        m_volumes.release_geometry();
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
         m_volumes.clear();
         m_dirty = true;
     }
@@ -1917,7 +1919,9 @@ void GLCanvas3D::reload_scene(bool refresh_immediately, bool force_full_scene_re
                     assert(volume_idx_wipe_tower_old == -1);
                     volume_idx_wipe_tower_old = (int)volume_id;
                 }
-                volume->release_geometry();
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+//                volume->release_geometry();
+//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
                 if (! m_reload_delayed)
                     delete volume;
             } else {
@@ -4474,7 +4478,6 @@ void GLCanvas3D::_load_print_toolpaths()
 
         _3DScene::extrusionentity_to_verts(print->skirt(), print_zs[i], Point(0, 0), volume);
     }
-    volume.indexed_vertex_array.finalize_geometry();
 }
 
 void GLCanvas3D::_load_print_object_toolpaths(const PrintObject& print_object, const std::vector<std::string>& str_tool_colors, const std::vector<double>& color_print_values)
@@ -4646,9 +4649,6 @@ void GLCanvas3D::_load_print_object_toolpaths(const PrintObject& print_object, c
 	            }
 	        }
         }
-        for (GLVolume *vol : vols) {
-            vol->indexed_vertex_array.shrink_to_fit();
-        }
     });
 
     BOOST_LOG_TRIVIAL(debug) << "Loading print object toolpaths in parallel - finalizing results";
@@ -4657,8 +4657,6 @@ void GLCanvas3D::_load_print_object_toolpaths(const PrintObject& print_object, c
         std::remove_if(m_volumes.volumes.begin() + volumes_cnt_initial, m_volumes.volumes.end(),
         [](const GLVolume *volume) { return volume->empty(); }),
         m_volumes.volumes.end());
-    for (size_t i = volumes_cnt_initial; i < m_volumes.volumes.size(); ++i)
-        m_volumes.volumes[i]->indexed_vertex_array.finalize_geometry();
 
     BOOST_LOG_TRIVIAL(debug) << "Loading print object toolpaths in parallel - end";
 }
@@ -4814,9 +4812,6 @@ void GLCanvas3D::_load_wipe_tower_toolpaths(const std::vector<std::string>& str_
                 vol_new.indexed_vertex_array.reserve(ctxt.alloc_size_reserve());
             }
         }
-        for (GLVolume *vol : vols) {
-            vol->indexed_vertex_array.shrink_to_fit();
-        }
     });
 
     BOOST_LOG_TRIVIAL(debug) << "Loading wipe tower toolpaths in parallel - finalizing results";
@@ -4825,8 +4820,6 @@ void GLCanvas3D::_load_wipe_tower_toolpaths(const std::vector<std::string>& str_
         std::remove_if(m_volumes.volumes.begin() + volumes_cnt_initial, m_volumes.volumes.end(),
         [](const GLVolume *volume) { return volume->empty(); }),
         m_volumes.volumes.end());
-    for (size_t i = volumes_cnt_initial; i < m_volumes.volumes.size(); ++i)
-        m_volumes.volumes[i]->indexed_vertex_array.finalize_geometry();
 
     BOOST_LOG_TRIVIAL(debug) << "Loading wipe tower toolpaths in parallel - end";
 }
@@ -5003,16 +4996,6 @@ void GLCanvas3D::_load_gcode_extrusion_paths(const GCodePreviewData& preview_dat
             }
         }
     }
-
-    // finalize volumes and sends geometry to gpu
-    if (m_volumes.volumes.size() > initial_volumes_count)
-    {
-        for (size_t i = initial_volumes_count; i < m_volumes.volumes.size(); ++i)
-        {
-            GLVolume* volume = m_volumes.volumes[i];
-            volume->indexed_vertex_array.finalize_geometry();
-        }
-    }
 }
 
 void GLCanvas3D::_load_gcode_travel_paths(const GCodePreviewData& preview_data, const std::vector<float>& tool_colors)
@@ -5057,16 +5040,6 @@ void GLCanvas3D::_load_gcode_travel_paths(const GCodePreviewData& preview_data,
 
         return;
     }
-
-    // finalize volumes and sends geometry to gpu
-    if (m_volumes.volumes.size() > initial_volumes_count)
-    {
-        for (size_t i = initial_volumes_count; i < m_volumes.volumes.size(); ++i)
-        {
-            GLVolume* volume = m_volumes.volumes[i];
-            volume->indexed_vertex_array.finalize_geometry();
-        }
-    }
 }
 
 bool GLCanvas3D::_travel_paths_by_type(const GCodePreviewData& preview_data)
@@ -5295,9 +5268,6 @@ void GLCanvas3D::_load_gcode_retractions(const GCodePreviewData& preview_data)
 
             _3DScene::point3_to_verts(position.position, position.width, position.height, *volume);
         }
-
-        // finalize volumes and sends geometry to gpu
-        volume->indexed_vertex_array.finalize_geometry();
     }
 }
 
@@ -5325,9 +5295,6 @@ void GLCanvas3D::_load_gcode_unretractions(const GCodePreviewData& preview_data)
 
             _3DScene::point3_to_verts(position.position, position.width, position.height, *volume);
         }
-
-        // finalize volumes and sends geometry to gpu
-        volume->indexed_vertex_array.finalize_geometry();
     }
 }
 
@@ -5419,8 +5386,6 @@ void GLCanvas3D::_load_sla_shells()
             double shift_z = obj->get_current_elevation();
             for (unsigned int i = initial_volumes_count; i < m_volumes.volumes.size(); ++ i) {
                 GLVolume& v = *m_volumes.volumes[i];
-                // finalize volumes and sends geometry to gpu
-                v.indexed_vertex_array.finalize_geometry();
                 // apply shift z
                 v.set_sla_shift_z(shift_z);
             }