Polar Pattern count missmatch

[freedman]

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]

For the angle of the polar pattern you can use Expressions, i.e in your case you enter Revolution.Angle.

[chrisb]

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]

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 (35.38 KiB) Viewed 928 times

the sketch is shown in white instead of green and the solver tells me

Bildschirmfoto 2018-07-22 um 10.33.14.png (10.08 KiB) Viewed 928 times

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]

In case it helps, I have minimized the "unsolved" producing model:

[freedman]

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]

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 (299.46 KiB) Viewed 910 times

[abdullah]

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...

abdullah

is this interesting for you?

[chrisb]

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]

Could you create a ticket with it so that it does not get lost?

I added a reference to this topic in issue #3589