Slot polar occurrences fail on spherical faces

Post here for help on using FreeCAD's graphical user interface (GUI).
Forum rules
and Helpful information
IMPORTANT: Please click here and read this first, before asking for help

Also, be nice to others! Read the FreeCAD code of conduct!
User avatar
ppemawm
Posts: 518
Joined: Fri May 17, 2013 3:54 pm
Location: Manhattan New York

Slot polar occurrences fail on spherical faces

Postby ppemawm » Sat Apr 25, 2015 1:45 pm

This is either a bug or I am probably doing something incorrectly. Please see attached file.
slot_polar_pattern_FAIL.FCStd
(324.58 KiB) Downloaded 39 times
I am trying to add six (6) slots to a rather simple revolution that includes two spherical faces. As the file shows, there are three versions of the revolution. The first revolution with radial or conical sides succeeds with polar pattern occurrences up to 24. The other two which include one or two spherical faces fail at various occurrences:
slot_polar_pattern_FAIL.JPG
slot_polar_pattern_FAIL.JPG (88.15 KiB) Viewed 1446 times
All three models pass Check Geometry with Run BOP Check 'true'. This must have something to do with the spherical faces or am I missing something else?

Thanks in advance for any help.

OS: Windows 8.1
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.15.4671 (Git)
Branch: releases/FreeCAD-0-15
Hash: 244b3aef360841646cbfe80a1b225c8b39c8380c
Python version: 2.7.8
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17
"It is a poor workman who blames his tools..." ;)
User avatar
quick61
Posts: 3793
Joined: Sat Aug 24, 2013 2:49 am
Location: u.S.A.

Re: Slot polar occurrences fail on spherical faces

Postby quick61 » Sat Apr 25, 2015 2:31 pm

I just changed the value of occurrences in the failed polar pattern to 5 and did a recompute then back to 6 and after another recompute, it is working as expected. Give that a try and see what happens. Maybe a little bug in OCE?

Mark
This post made with 0.0% Micro$oft products - GOT LINUX?
User avatar
sgrogan
Posts: 5241
Joined: Wed Oct 22, 2014 5:02 pm

Re: Slot polar occurrences fail on spherical faces

Postby sgrogan » Sat Apr 25, 2015 2:44 pm

quick61 wrote:I just changed the value of occurrences in the failed polar pattern to 5 and did a recompute then back to 6 and after another recompute, it is working as expected. Give that a try and see what happens. Maybe a little bug in OCE?
I did the same and 6 worked. I opened PolarPattern002 and it now fails at 6 occurrences.
User avatar
ppemawm
Posts: 518
Joined: Fri May 17, 2013 3:54 pm
Location: Manhattan New York

Re: Slot polar occurrences fail on spherical faces

Postby ppemawm » Sat Apr 25, 2015 3:01 pm

sgrogan wrote:I did the same and 6 worked. I opened PolarPattern002 and it now fails at 6 occurrences.
I had done the same as quick1 and sgrogan but 5 failed and 6 succeeded with recompute, sometimes. Seems a bit random. Good thing I only need six and not ten or some other number.
"It is a poor workman who blames his tools..." ;)
User avatar
DeepSOIC
Posts: 6844
Joined: Fri Aug 29, 2014 12:45 am
Location: Saint-Petersburg, Russia

Re: Slot polar occurrences fail on spherical faces

Postby DeepSOIC » Sat Apr 25, 2015 3:45 pm

After a forced recompute, all cuts worked a treat in:
OS: Windows 8.1
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.4783 +1 (Git)
Branch: unlim_externals
Hash: e37a182c417fa3fe35ad3f7b15709e2f344cafd4
Python version: 2.7.8
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 6.7.1
I don't feel like upgrading myself to OCC6.8.0, I saw a few other cases where OCC6.7.1's Boolean operations were more successful.
slot_polar_pattern_no-fail.png
slot_polar_pattern_no-fail.png (52.38 KiB) Viewed 1415 times
EDIT: just tested in:
OS: Windows 8.1
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.15.4669 (Git)
Branch: releases/FreeCAD-0-15
Hash: d8bbbc1d1d111bd600025b2ba83f41b7353e3790
Python version: 2.7.8
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17
And it worked just fine!

EDIT2: but if I bump up the occurences, I strart getting skips too, even in OCC6.7.1. So consider that confirmed.
User avatar
bejant
Posts: 5805
Joined: Thu Jul 11, 2013 3:06 pm

Re: Slot polar occurrences fail on spherical faces

Postby bejant » Sat Apr 25, 2015 6:47 pm

For me Check Geometry with BOPcheck = True reports that Pocket001 and Pocket002 are invalid, and so the PolarPatterns fail too.
User avatar
ppemawm
Posts: 518
Joined: Fri May 17, 2013 3:54 pm
Location: Manhattan New York

Re: Slot polar occurrences fail on spherical faces

Postby ppemawm » Sat Apr 25, 2015 9:11 pm

bejant wrote:For me Check Geometry with BOPcheck = True reports that Pocket001 and Pocket002 are invalid,
So it appears that the radiused slot is the culprit even though my Check Geometry does not pick it up. A workaround is to first pocket a hole, polar pattern the hole, pocket a rectangular slot, then polar pattern the slot:
polar_slot_work_around.JPG
polar_slot_work_around.JPG (28.07 KiB) Viewed 1391 times
Should a bug report be submitted?
"It is a poor workman who blames his tools..." ;)
User avatar
quick61
Posts: 3793
Joined: Sat Aug 24, 2013 2:49 am
Location: u.S.A.

Re: Slot polar occurrences fail on spherical faces

Postby quick61 » Sat Apr 25, 2015 9:26 pm

Try a Sketch like this -
NewSketch.png
NewSketch.png (35.16 KiB) Viewed 1387 times
Remove the unneeded arc and it's tangents from the outside and replace with a line. I think it will work better than you had and be less work than making 2 polar patterns.

No Errors in check geometry with BOPCheck.

Mark
This post made with 0.0% Micro$oft products - GOT LINUX?
User avatar
DeepSOIC
Posts: 6844
Joined: Fri Aug 29, 2014 12:45 am
Location: Saint-Petersburg, Russia

Re: Slot polar occurrences fail on spherical faces

Postby DeepSOIC » Sun Apr 26, 2015 1:12 am

BTW, I just noticed that your faces are not spherical, as you stated. For them to be spherical, arc's centers must lie on axis of revolution. They don't. If I make them actually spherical, I can get all 24 slots in the leftmost piece, no problem.

The fact that faces are not spherical isn't an excuse for the cuts to fail, though...
Attachments
slot_polar_pattern_sphere.FCStd
(316.29 KiB) Downloaded 11 times
User avatar
ppemawm
Posts: 518
Joined: Fri May 17, 2013 3:54 pm
Location: Manhattan New York

Re: Slot polar occurrences fail on 'curved' faces

Postby ppemawm » Sun Apr 26, 2015 1:14 pm

quick61 wrote:Remove the unneeded arc and it's tangents from the outside and replace with a line.
I had tried that earlier but it fails at 4,5, and >6 occurrences, at least in my file. I get the same failed result if the tangency constraint is removed and the slot extended radially a small amount.
DeepSOIC wrote:BTW, I just noticed that your faces are not spherical, as you stated.The fact that faces are not spherical isn't an excuse for the cuts to fail, though...
Thanks for the correction. It is important to be both accurate and precise. I tried your spherical version, and it fails the same as above for me.

If we agree this is a bug then I will submit a report.
"It is a poor workman who blames his tools..." ;)