diff --git a/src/libslic3r/PrintObject.cpp b/src/libslic3r/PrintObject.cpp
index d2c8ec054..b0705873d 100644
--- a/src/libslic3r/PrintObject.cpp
+++ b/src/libslic3r/PrintObject.cpp
@@ -723,7 +723,14 @@ bool PrintObject::invalidate_state_by_config_options(
             || opt_key == "support_top_z_distance"
             || opt_key == "support_bottom_z_distance"
             || opt_key == "xy_hole_compensation"
-            || opt_key == "xy_contour_compensation") {
+            || opt_key == "xy_contour_compensation"
+            //BBS: [Arthur] the following params affect bottomBridge surface type detection
+            || opt_key == "support_type"
+            || opt_key == "bridge_no_support"
+            || opt_key == "max_bridge_length"
+            || opt_key == "support_interface_top_layers"
+            || opt_key == "support_critical_regions_only"
+            ) {
             steps.emplace_back(posSlice);
         } else if (opt_key == "enable_support") {
             steps.emplace_back(posSupportMaterial);
@@ -970,9 +977,17 @@ void PrintObject::detect_surfaces_type()
             [this, region_id, interface_shells, &surfaces_new](const tbb::blocked_range<size_t>& range) {
                 // If we have soluble support material, don't bridge. The overhang will be squished against a soluble layer separating
                 // the support from the print.
-                SurfaceType surface_type_bottom_other =
-                    (this->has_support() && m_config.support_top_z_distance.value == 0) ?
-                    stBottom : stBottomBridge;
+                // BBS: the above logic only applys for normal(auto) support. Complete logic:
+                // 1. has support, top z distance=0 (soluble material), auto support
+                // 2. for normal(auto), bridge_no_support is off
+                // 3. for tree(auto), interface top layers=0, max bridge length=0, support_critical_regions_only=false (only in this way the bridge is fully supported)
+                bool bottom_is_fully_supported = this->has_support() && m_config.support_top_z_distance.value == 0 && is_auto(m_config.support_type.value);
+                if (m_config.support_type.value == stNormalAuto)
+                    bottom_is_fully_supported &= !m_config.bridge_no_support.value;
+                else if (m_config.support_type.value == stTreeAuto) {
+                    bottom_is_fully_supported &= (m_config.support_interface_top_layers.value > 0 && m_config.max_bridge_length.value == 0 && m_config.support_critical_regions_only.value==false);
+                }
+                SurfaceType surface_type_bottom_other = bottom_is_fully_supported ? stBottom : stBottomBridge;
                 for (size_t idx_layer = range.begin(); idx_layer < range.end(); ++ idx_layer) {
                     m_print->throw_if_canceled();
                     // BOOST_LOG_TRIVIAL(trace) << "Detecting solid surfaces for region " << region_id << " and layer " << layer->print_z;