diff --git a/src/slic3r/GUI/GCodeViewer.cpp b/src/slic3r/GUI/GCodeViewer.cpp
index c106ed01ec..3737c7021c 100644
--- a/src/slic3r/GUI/GCodeViewer.cpp
+++ b/src/slic3r/GUI/GCodeViewer.cpp
@@ -1236,15 +1236,12 @@ void GCodeViewer::render(int canvas_width, int canvas_height, int right_margin)
     m_statistics.total_instances_gpu_size = 0;
 #endif // ENABLE_GCODE_VIEWER_STATISTICS
 
-    render_shells();
-    // Orca: add shell overlay effect
-    glsafe(::glClear(GL_DEPTH_BUFFER_BIT));
-
     if (m_roles.empty())
         return;
-    glsafe(::glEnable(GL_DEPTH_TEST));
 
+    glsafe(::glEnable(GL_DEPTH_TEST));
     render_toolpaths();
+    render_shells();
     float legend_height = 0.0f;
     render_legend(legend_height, canvas_width, canvas_height, right_margin);
 
@@ -4115,16 +4112,16 @@ void GCodeViewer::render_shells()
     if (shader == nullptr)
         return;
 
-    glsafe(::glEnable(GL_DEPTH_TEST));
 //    glsafe(::glDepthMask(GL_FALSE));
 
     shader->start_using();
+    shader->set_uniform("emission_factor", 0.1f);
     const Camera& camera = wxGetApp().plater()->get_camera();
-    //BBS: reopen cul faces
-    m_shells.volumes.render(GLVolumeCollection::ERenderType::Transparent, false, camera.get_view_matrix(), camera.get_projection_matrix());
+    m_shells.volumes.render(GLVolumeCollection::ERenderType::Transparent, true, camera.get_view_matrix(), camera.get_projection_matrix());
+    shader->set_uniform("emission_factor", 0.0f);
     shader->stop_using();
 
-    //    glsafe(::glDepthMask(GL_TRUE));
+//    glsafe(::glDepthMask(GL_TRUE));
 }
 
 //BBS