Polar Pattern count missmatch

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freedman
Posts: 855
Joined: Thu Mar 22, 2018 3:02 am
Location: Washington State, USA

Re: Polar Pattern count missmatch

Postby freedman » Sun Jul 22, 2018 7:33 am

So we have to remember to add one extra unless it's a full circle. I'm not very good at remembering stuff like that but I also don't see any other way to do it.
Am I right, then in thinking the degrees is to the start of the final occurrence rather than after it
I guess they had to do that because there really is no reliable way to know the width of the pocket feature. But they do it in a full circle. Hmmm.
chrisb
Posts: 17593
Joined: Tue Mar 17, 2015 9:14 am

Re: Polar Pattern count missmatch

Postby chrisb » Sun Jul 22, 2018 7:49 am

For the angle of the polar pattern you can use Expressions, i.e in your case you enter Revolution.Angle.
chrisb
Posts: 17593
Joined: Tue Mar 17, 2015 9:14 am

Re: Polar Pattern count missmatch

Postby chrisb » Sun Jul 22, 2018 8:17 am

Here is an even better expression, which uses the number of occurrences and respects the angle:

Code: Select all

Revolution.Angle * (Occurrences-1) / Occurrences
which is the same as

Code: Select all

Revolution.Angle * (1 - 1 / Occurrences)
chrisb
Posts: 17593
Joined: Tue Mar 17, 2015 9:14 am

Re: Polar Pattern count missmatch

Postby chrisb » Sun Jul 22, 2018 8:35 am

When fiddling around because I had the feeling that it contained too much I found something interesting in Sketch002:
When I delete the selected construction line at the right bottom
Bildschirmfoto 2018-07-22 um 10.29.08.png
Bildschirmfoto 2018-07-22 um 10.29.08.png (35.38 KiB) Viewed 160 times
the sketch is shown in white instead of green and the solver tells me
Bildschirmfoto 2018-07-22 um 10.33.14.png
Bildschirmfoto 2018-07-22 um 10.33.14.png (10.08 KiB) Viewed 160 times
abdullah wrote:abdullah
is this interesting for you?

OS: Mac OS X
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.13976 (Git)
Build type: Release
Branch: (HEAD detached at fae0de5)
Hash: fae0de58581694157a97d567c151bdce75d387dc
Python version: 2.7.15
Qt version: 5.11.0
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: German/Germany (de_DE)
chrisb
Posts: 17593
Joined: Tue Mar 17, 2015 9:14 am

Re: Polar Pattern count missmatch

Postby chrisb » Sun Jul 22, 2018 8:49 am

In case it helps, I have minimized the "unsolved" producing model:
Attachments
Gear_cb.FCStd
(3.42 KiB) Downloaded 7 times
freedman
Posts: 855
Joined: Thu Mar 22, 2018 3:02 am
Location: Washington State, USA

Re: Polar Pattern count missmatch

Postby freedman » Sun Jul 22, 2018 6:28 pm

Postby chrisb » Sun Jul 22, 2018 12:17 am
Here is an even better expression, which uses the number of occurrences and respects the angle:

Code: Select all

Revolution.Angle * (Occurrences-1) / Occurrences

which is the same as

Code: Select all

Revolution.Angle * (1 - 1 / Occurrences)
Can you post how these are to be used in the GUI.
Thanks
TheMarkster
Posts: 1055
Joined: Thu Apr 05, 2018 1:53 am

Re: Polar Pattern count missmatch

Postby TheMarkster » Sun Jul 22, 2018 7:33 pm

chrisb wrote:
Sun Jul 22, 2018 6:45 am
The misunderstanding might be the following:
The angle defines where the last occurrence starts, not where it ends. The case 360° might lead to confusion, because it is treated special by guessing that you in fact want to have the occurrences distributed evenly around the whole circle.
Ah, now I see. 360° is treated specially. I was wondering about that. Angle would be from start of first element to start of last element, thus we can expect the same results for 12 elements in a full circle with either 360° or 360 * 11/12 (330°).

Note also how 360.0° is treated differently from 360.01° (with draft array)
polar angles.gif
polar angles.gif (299.46 KiB) Viewed 142 times
abdullah
Posts: 3174
Joined: Sun May 04, 2014 3:16 pm

Re: Polar Pattern count missmatch

Postby abdullah » Thu Sep 20, 2018 6:31 pm

Sure it is!

I do not have much time ATM. I have played with the reduced sketch and the behaviour does not seem right. Could you create a ticket with it so that it does not get lost? I might not be available until Mid-October...
chrisb wrote:
Sun Jul 22, 2018 8:35 am
abdullah wrote:abdullah
is this interesting for you?
chrisb
Posts: 17593
Joined: Tue Mar 17, 2015 9:14 am

Re: Polar Pattern count missmatch

Postby chrisb » Thu Sep 20, 2018 6:43 pm

abdullah wrote:
Thu Sep 20, 2018 6:31 pm
Could you create a ticket with it so that it does not get lost?
Voluntary; I will do so in the next days, I have the feeling that I could even simplify it further and I might have created a ticket.
chrisb
Posts: 17593
Joined: Tue Mar 17, 2015 9:14 am

Re: Polar Pattern count missmatch

Postby chrisb » Fri Sep 21, 2018 1:34 pm

chrisb wrote:
Thu Sep 20, 2018 6:43 pm
Could you create a ticket with it so that it does not get lost?
I added a reference to this topic in issue #3589