diff --git a/src/lib/geogram/mesh/mesh_surface_intersection_internal.cpp b/src/lib/geogram/mesh/mesh_surface_intersection_internal.cpp
index 0c2859826a6f..1ed549f3b536 100644
--- a/src/lib/geogram/mesh/mesh_surface_intersection_internal.cpp
+++ b/src/lib/geogram/mesh/mesh_surface_intersection_internal.cpp
@@ -853,6 +853,17 @@ namespace GEO {
 
         point_.push_back(mix(t, point_[i], point_[j]));
         Numeric::optimize_number_representation(*point_.rbegin());
+
+#ifndef INTERSECTIONS_USE_EXACT_NT
+        {
+            const ExactPoint& p = *point_.rbegin();
+            length_.push_back(
+                (geo_sqr(p.x) + geo_sqr(p.y)).estimate() /
+                geo_sqr(p.w).estimate() 
+            );
+        }
+#endif            
+
         
         id_.push_back(index_t(-1));
         index_t x = point_.size()-1;