Added test case bugs/modalg_6/bug21821
--- /dev/null
+set subgroup modalg
+
+set calcul "p"
+set type "i"
+
+proc OFFSETSHAPE {distance faces calcul type} {
+ uplevel #0 explode s f
+ uplevel #0 offsetparameter 1e-7 $calcul $type
+ uplevel #0 offsetload s $distance $faces
+ uplevel #0 offsetperform result
+}
+
+
+
+
+
+
+
+
+
--- /dev/null
+puts "=========="
+puts "OCC21821"
+puts "=========="
+puts ""
+############################################################
+# Section of face by plane is not built due to small edges
+############################################################
+
+restore [locate_data_file bug21821_plane_tailtop.brep] a
+
+plane p 28.85 0 0 1 0 0
+mkface f p -10 10 -10 10
+bsection result a f
+
+set length 2.95277
+smallview
+clear
+display result
+display f
+display a
+fit
+set only_screen_axo 1