0032932: Fillet fails in PerformIntersectionAtEnd because no face was found - MantisBT

ID	Project	Category	View Status	Date Submitted	Last Update

0032932	Community	OCCT:Modeling Algorithms	public	2022-04-13 15:32	2022-04-13 16:01

Reporter	CharlemagneLasse	Assigned To	~~azv~~
Priority	normal	Severity	minor
Status	new	Resolution	open
Platform	Linux	OS	Debian bullseye amd64
Product Version	7.5.3

Summary	0032932: Fillet fails in PerformIntersectionAtEnd because no face was found
Description	(This problem was seen with the version bundled with FreeCAD 0.20.28445 but can be reproduced easily with the master version directly from OCCT) The PerformIntersectionAtEnd code is currently not handling all the faces correctly. If it retrieves Face[0] as F, it can happen that the previously ran code didn't actually retrieve any faces in this array at all. For example when: * "if (nface==3)" is true - "if (!findonf1)" is true (doesn't assign any faces to this array) - "if (!findonf2)" is true (doesn't assign any faces to this array) - "if (state == ChFiDS_OnSame)" is not true (because it is ChFiDS_AllSame) - "if (findonf1 && !isOnSame1)" cannot be true (see above, but would handle faces) - "if (findonf2 && !isOnSame2)" cannot be true (see above, but would handle faces) - "if (isOnSame2)" is false (but would also handle faces) Since no faces were assigned here, F would be a NULL face. Without the change from 0032930, the process will simply segfault. But even with the changes from 0032930, the fillet will not be created. More information (including how it was debugged) can be found at: * https://github.com/FreeCAD/FreeCAD/issues/6625#issuecomment-1094139670 * https://forum.freecadweb.org/viewtopic.php?p=584239#p584239
Steps To Reproduce	# get most recent OCCT $ cd /tmp/ $ git clone https://git.dev.opencascade.org/repos/occt.git OCCT # get build dependencies based on opencascade package in the Debian package source (deb-src) repository. will most likely work differently on whatever Distro you are using $ sudo apt build-dep opencascade # build everything (I only have 4 cores - you might change it if you are not working on a system with a 10 year old CPU) $ cd OCCT $ mkdir build $ cd build $ cmake .. -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_COMPILER_LAUNCHER=ccache -DCMAKE_VERBOSE_MAKEFILE=true && make -j4 $ cd /tmp/ # figure out how the brp of the last Pad (name "Pad") is called: $ unzip -p tutorial_excercise_1.FCStd Document.xml\|xmllint --xpath 'string(//Document/ObjectData/Object/Properties/Property[@name="Label"]/String[@value="Pad"]/../../Property[@name="Shape"]/Part/@file)' /dev/stdin PartShape3.brp # extract the PartShape3.brp for later usage - WARNING, the step with adding the extra header is only necessary in case it wasn't saved by FreeCAD. Versions before 4aa09e317f7be81a906439ff4bc08a4b4e8043ba will not be able to load this file if this header is not present $ rm -f PartShape3.brp $ echo DBRep_DrawableShape > PartShape3.brp $ unzip -p tutorial_excercise_1.FCStd PartShape3.brp >> PartShape3.brp # prepare reproducer script $ cd /tmp/OCCT/ $ cat > test.script << "EOF" # load the brp, get edges and then try to add fillet on the problematic edge Edge10 pload ALL restore /tmp/PartShape3.brp b explode b E blend b b 1 b_10 EOF # start DRAWEXE shell # usually I would have done it like that. But it is then not 100% reproducible due to various system effects. # So I just use gdb in the actual command to improve my live and make it 100% reproducible #$ LD_LIBRARY_PATH=/tmp/OCCT/build/lin64/gcc/libd/ CASROOT=/tmp/OCCT ./build/lin64/gcc/bind/DRAWEXE -f test.script $ LD_LIBRARY_PATH=/tmp/OCCT/build/lin64/gcc/libd/ CASROOT=/tmp/OCCT gdb -q --ex run --args ./build/lin64/gcc/bind/DRAWEXE -f test.script
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Date Modified	Username	Field	Change
2022-04-13 15:32	CharlemagneLasse	New Issue
2022-04-13 15:32	CharlemagneLasse	Assigned To	=> msv
2022-04-13 15:32	CharlemagneLasse	File Added: PartShape3.brp
2022-04-13 16:01	~~msv~~	Assigned To	msv => azv