Polar pattern without rotating feature

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Marc Bassini
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Polar pattern without rotating feature

Post by Marc Bassini »

Hello.

The back of the chair I'm working on has two parts.
The bottom one is a straight line.
The upper one is an arc of a circle (green edge on screen shot).

I need to distribute the mortises along these two parts.
Easy for the bottom part.
But for the arc I need to use a Polar pattern but the mortise must not be rotated (must remain vertical).

Is it possible to do so ?

Thanks
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thomas-neemann
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Re: Polar pattern without rotating feature

Post by thomas-neemann »

I didn't find anything in partdesign. is that a solution for you?


https://www.youtube.com/watch?v=svOFrTBySp4

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Re: Polar pattern without rotating feature

Post by chrisb »

A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
Marc Bassini
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Re: Polar pattern without rotating feature

Post by Marc Bassini »

thomas-neemann wrote: Mon Dec 06, 2021 11:32 pm I didn't find anything in partdesign. is that a solution for you?
Yes, it did the work.

This way I discovered I was wrong on using Polar distribution for the upper part.
What I actually want is to have the same vertical space between the bars of the back.
So I need to :
1- distribute the mortises vertically
2- project them horizontally on the back curve (cause I want the same shoulder on all the tenons).

Have to figure out how to achieve point 2.
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thomas-neemann
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Re: Polar pattern without rotating feature

Post by thomas-neemann »

Marc Bassini wrote: Tue Dec 07, 2021 2:18 pm
you can upload the file and a hand sketch of how it should be
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Marc Bassini
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Re: Polar pattern without rotating feature

Post by Marc Bassini »

Here is an example.
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Re: Polar pattern without rotating feature

Post by thomas-neemann »

Marc Bassini wrote: Tue Dec 07, 2021 3:27 pm
is that a solution?

https://www.youtube.com/watch?v=nrtH2bLwNfE

phpBB [video]
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Marc Bassini
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Re: Polar pattern without rotating feature

Post by Marc Bassini »

Unfortunatly not.
They are not evenly distributed along the z axis
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thomas-neemann
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Re: Polar pattern without rotating feature

Post by thomas-neemann »

Marc Bassini wrote: Tue Dec 07, 2021 9:17 pm ...Unfortunatly not.
..

is that a solution for you?
902.FCStd
(43.36 KiB) Downloaded 14 times

https://www.youtube.com/watch?v=JfcAowEwS6A

phpBB [video]


OS: Ubuntu 20.04.1 LTS (XFCE/xubuntu)
Word size of FreeCAD: 64-bit
Version: 0.20.26554 (Git) AppImage
Build type: Release
Branch: (HEAD detached at 817c14b)
Hash: 817c14b16af681b06aec7d8c79f744c7a88fa3c3
Python version: 3.9.7
Qt version: 5.12.9
Coin version: 4.0.0
OCC version: 7.5.3
Locale: German/Germany (de_DE)
Gruß Dipl.-Ing. (FH) Thomas Neemann

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Marc Bassini
Posts: 135
Joined: Fri Aug 13, 2021 10:08 am

Re: Polar pattern without rotating feature

Post by Marc Bassini »

Yes... but no.

It does place the mortises at the correct positions.
But my example was also doing that.
And the flaw of both methods is that they are both handmade.

My chair is entirely build upon variables in a spreadsheet (see below).
I have no idea how many bars there will be.
I plan to use this project to design various chairs simply by modifying those variables.
So I need a method to dynamically distribute the mortises along the back.

I am using realthunder's version.
This version has the possibility to distribute features using GenericPattern method.
It is my understanding that this method allows to call external python code.
I used to be a programmer when dinosaurs were still alive.
Maybe this is the solution for my problem (the edges of the sketch of the back feet are mostly computed; I dont use fillets or tangent constrains but I compute the centers of the arcs instead to have complete control over the positions of edges and lengths of arcs; so I may also compute the positions of all the mortises if needed)
But I can't find any documentation about GenericPattern and calling external code.
Is anyone familiar with this tool?
Or can point me on some documentation?

Thanks
Attachments
chair.png
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