From 35d1221827afdc571d2aaa1e648a12fd86834166 Mon Sep 17 00:00:00 2001
From: apn <apn@opencascade.com>
Date: Mon, 20 Apr 2015 16:54:46 +0300
Subject: [PATCH] 0021351: Fail to compute derivatives of offset surface on
 trimmed surfaces on offsets on CN surfaces

Added test case bugs/modalg_6/bug21351
---
 tests/bugs/modalg_6/bug21351 | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 tests/bugs/modalg_6/bug21351

diff --git a/tests/bugs/modalg_6/bug21351 b/tests/bugs/modalg_6/bug21351
new file mode 100644
index 0000000000..5059a4bc57
--- /dev/null
+++ b/tests/bugs/modalg_6/bug21351
@@ -0,0 +1,20 @@
+puts "=========="
+puts "OCC23351"
+puts "=========="
+puts ""
+################################################################################################
+# Fail to compute derivatives of offset surface on trimmed surfaces on offsets on CN surfaces
+################################################################################################
+
+beziersurf bz 3 3 0 0 0 1 -1 0 2 0 0 0 -1 1 1 0 1 2 -1 1 0 0 2 1 -1 2 2 0 2
+offset obz bz 0.5
+trim tobz obz 0.1 0.9 0.1 0.9
+offset otobz tobz 0.5
+svalue otobz 0.2 0.2 x y z dux duy duz dvx dvy dvz
+
+offset oobz bz 1
+svalue oobz 0.2 0.2 x y z dux duy duz dvx dvy dvz
+
+trim ttbz bz 0.1 0.9 0.1 0.9
+offset ottbz ttbz 1
+svalue ottbz 0.2 0.2 x y z dux duy duz dvx dvy dvz
-- 
2.20.1