filter out tiny gaps

src/libslic3r/Fill/FillRectilinear.cpp

@@ -3169,9 +3169,17 @@ void FillMonotonicLineWGapFill::fill_surface_extrusion(const Surface* surface, c
         }
 
         if (!polylines.empty() && !is_bridge(params.extrusion_role)) {
+            if (!surface->is_top() && !surface->is_bottom()) {
+                polylines.erase(std::remove_if(polylines.begin(), polylines.end(),
+                    [&](const ThickPolyline& p) {
+                        return p.length() < scale_(params.config->filter_out_gap_fill.value);
+                    }), polylines.end());
+            }
+
             ExtrusionEntityCollection gap_fill;
             variable_width(polylines, erGapFill, params.flow, gap_fill.entities);
             coll_nosort->append(std::move(gap_fill.entities));
+
         }
     }