From afef5597b23525d82561c7d280c4e6a8d9592efc Mon Sep 17 00:00:00 2001
From: Dario Sassi <dario.sassi@egalware.com>
Date: Mon, 12 Jan 2026 08:15:06 +0100
Subject: [PATCH] EgtGeomKernel : - tentaivo di correzione intersezione tra
 segmenti di retta quasi paralleli.

---
 IntersLineLine.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/IntersLineLine.cpp b/IntersLineLine.cpp
index 896df6c..c87691c 100644
--- a/IntersLineLine.cpp
+++ b/IntersLineLine.cpp
@@ -158,6 +158,16 @@ IntersLineLine::IntersFiniteLines( const CurveLine& Line1, const CurveLine& Line
    bool bParallel = ( abs( dCrossXY) < SIN_EPS_ANG_ZERO * ( dLen1XY * dLen2XY)) ;
   // flag per segmenti che si allontanano significativamente
    bool bFarEnds = ( nS1Side != 0  ||  nE1Side != 0  ||  nS2Side != 0  ||  nE2Side != 0) ;
+  // analisi casi speciali di quasi parallelismo 
+   if ( ! bParallel  &&  abs( dCrossXY) < ( 0.1 * DEGTORAD) * ( dLen1XY * dLen2XY)) {
+      if (( nS1Side == 0  &&  nS2Side == 0  &&  ! AreSamePointXYEpsilon( ptS1, ptS2, 2 * EPS_SMALL))  ||
+          ( nS1Side == 0  &&  nE2Side == 0  &&  ! AreSamePointXYEpsilon( ptS1, ptE2, 2 * EPS_SMALL))  ||
+          ( nE1Side == 0  &&  nS2Side == 0  &&  ! AreSamePointXYEpsilon( ptE1, ptS2, 2 * EPS_SMALL))  ||
+          ( nE1Side == 0  &&  nE2Side == 0  &&  ! AreSamePointXYEpsilon( ptE1, ptE2, 2 * EPS_SMALL))) {
+         bParallel = true ;
+         bFarEnds = false ;
+      }
+   }
 
   // se non sono paralleli e si allontanano tra loro abbastanza
    if ( ! bParallel  &&  bFarEnds) {