From 8db2413c8419d499ed9181a63d4dd2b0d14cae1e Mon Sep 17 00:00:00 2001
From: Alessio Quaglino <quaglino@google.com>
Date: Mon, 28 Jul 2025 04:39:58 -0700
Subject: [PATCH] Fix a bug in triangle-box filter that caused missing Octree
 leaves.

PiperOrigin-RevId: 787955811
Change-Id: I40ad0f9219cbe5d5757b9345b1de495cba50d306
---
 src/user/user_objects.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/user/user_objects.cc b/src/user/user_objects.cc
index 1e7a22e8..2eed2465 100644
--- a/src/user/user_objects.cc
+++ b/src/user/user_objects.cc
@@ -640,7 +640,7 @@ static bool boxTriangle(const Triangle& v, const double aamm[6]) {
     int c = (a + 2) % 3;
     for (int i = 0; i < 3; i++) {
       double sign = n[a] >= 0 ? 1 : -1;
-      double ne[2] = {-e[i][c] * sign, -e[i][b] * sign};
+      double ne[2] = {-e[i][c] * sign, e[i][b] * sign};
       double vi[2] = {v[i][b], v[i][c]};
       double d = -dot2(ne, vi) + mju_max(0, size[b]*ne[0]) + mju_max(0, size[c]*ne[1]);
       double p[2] = {aamm[b], aamm[c]};