From 1f47402215759ab4abc096033430841e34b1fad2 Mon Sep 17 00:00:00 2001
From: Daniele Bariletti <daniele.bariletti@egalware.com>
Date: Tue, 9 Jun 2026 16:50:20 +0200
Subject: [PATCH] EgtGeomKernel : - piccola correzione.

---
 IntersLineCyl.cpp | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/IntersLineCyl.cpp b/IntersLineCyl.cpp
index ae40e16..dc706d9 100644
--- a/IntersLineCyl.cpp
+++ b/IntersLineCyl.cpp
@@ -44,14 +44,17 @@ IntersLineCyl( const Point3d& ptP, const Vector3d& vtV, double dH, double dRad,
    int nBasInt = 0 ;
    if ( abs( vtV.z) > EPS_ZERO) {
       // le linee tangenti al cilindro non sono considerate intersecanti
+      double dEpsRad = ( vtV.IsZeroXY() ? - EPS_SMALL : EPS_SMALL) ;
+      if ( bIgnoreTap)
+         dEpsRad = 0. ;
       ptInt1 = ptP + ( ( 0 - ptP.z) / vtV.z) * vtV ;
-      if ( ptInt1.x * ptInt1.x + ptInt1.y * ptInt1.y < dRad * dRad) {
+      if ( ptInt1.x * ptInt1.x + ptInt1.y * ptInt1.y < dRad * dRad + 2 * dRad * dEpsRad) {
          nBasInt += 1 ;
          vtN1 = - Z_AX ;
          dU1 = ( ( 0 - ptP.z) / vtV.z) ;
       }
       ptInt2 = ptP + ( ( dH - ptP.z) / vtV.z) * vtV ;  
-      if ( ptInt2.x * ptInt2.x + ptInt2.y * ptInt2.y < dRad * dRad) {
+      if ( ptInt2.x * ptInt2.x + ptInt2.y * ptInt2.y < dRad * dRad + 2 * dRad * dEpsRad) {
          nBasInt += 2 ;
          vtN2 = Z_AX ;
          dU2 = ( ( dH - ptP.z) / vtV.z) ;
@@ -75,8 +78,8 @@ IntersLineCyl( const Point3d& ptP, const Vector3d& vtV, double dH, double dRad,
 
    // Determino le intersezioni con la superficie laterale del cilindro
    DBLVECTOR vdCoeff{ ptP.x * ptP.x + ptP.y * ptP.y - dRad * dRad,
-      2 * ( ptP.x * vtV.x + ptP.y * vtV.y),
-      vtV.x * vtV.x + vtV.y * vtV.y} ;
+                      2 * ( ptP.x * vtV.x + ptP.y * vtV.y),
+                      vtV.x * vtV.x + vtV.y * vtV.y} ;
    DBLVECTOR vdRoots ;
    int nRoot = PolynomialRoots( 2, vdCoeff, vdRoots) ;