Missing surfaces while boolean and brep

[GregoryLi0]

code version

BRL-CAD 7.32.4

OS version

win10 & ubuntu 20.04

Description

While operating boolean and brep, some surfaces are lost not as expected.

Steps to Reproduce the Issue

1. run shell cube_brep.sh:

# cube_brep.sh

CUBE="`basename $0`"

rm -f $CUBE.*

# create two arb8 solids
mged -c $CUBE.g in arb8.1 arb8 0 0 1  0 4 1  0 4 3  0 0 3  4 0 1  4 4 1  4 4 3  4 0 3
mged -c $CUBE.g in arb8.2 arb8 1 0 -1  1 2 -1  1 2 5  1 0 5  3 0 -1  3 2 -1  3 2 5  3 0 5

# boolean and brep
mged -c $CUBE.g r u.1 u arb8.1 u arb8.2
mged -c $CUBE.g brep u.1 brep b.1

# pipe in mged commands for setting up and saving the view to a render script
cat <<EOF | mged -c $CUBE.g
B b.1
ae 135 -65 180
saveview $CUBE.rt
B u.1
saveview $CUBE.expect.rt
EOF

# render the view we saved as a 1024x1024 image
./$CUBE.rt -s1024
./$CUBE.expect.rt -s1024

# convert from raw pix image format to png format
pix-png -s1024 < $CUBE.rt.pix > $CUBE.png
pix-png -s1024 < $CUBE.expect.rt.pix > $CUBE.expect.png

# keep the geometry database as cube_boolean.g and the rendering as cube_boolean.expect.png and cube_boolean.png
mv $CUBE.g cube_boolean.g
mv $CUBE.png cube_boolean.png
mv $CUBE.expect.png cube_boolean.expect.png

# clean up after ourselves
rm -f $CUBE.*
rm -f bool1*

The geometry database cube_boolean.g and the rendering png cube_boolean.expect.png and cube_boolean.png are generated.

Current Result

The rendering png:

Clearly, the output of boolean operation is wrong. Some surfaces did not generated properly.

Expected Result