How to create a polar pattern off axis

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!
Post Reply
PunyTune
Posts: 103
Joined: Sun Jan 06, 2019 1:59 am

How to create a polar pattern off axis

Post by PunyTune »

I wish to draw a disk, the center of which is not at the origin. Then I wish to put a hole near the rim of the disk, and use Polar Pattern to place additional holes around the circumference of the disk. But no matter what I try, the polar pattern is always referenced to the origin. If I draw the disk at the origin and add my holes, then move the disk, the holes stay at the origin. There has to be a way to reference my sketch instead of the origin, but "vertical" or "horizontal sketch axis" don't seem to do it.

OS: macOS Mojave (10.14)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.21775 (Git)
Build type: Release
Branch: master
Hash: 1f741aa511e898849e46ed14515fce416fe32acb
Python version: 3.8.2
Qt version: 5.12.5
Coin version: 4.0.0
OCC version: 7.4.0
Locale: C/Default (C)
Attachments
test.FCStd
(12.96 KiB) Downloaded 17 times
User avatar
thomas-neemann
Veteran
Posts: 11801
Joined: Wed Jan 22, 2020 6:03 pm
Location: Osnabrück DE 🇩🇪
Contact:

Re: How to create a polar pattern off axis

Post by thomas-neemann »

PunyTune wrote: Fri Jan 21, 2022 6:05 am ..Polar Pattern...
here is an example at min 4:50

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

phpBB [video]
Gruß Dipl.-Ing. (FH) Thomas Neemann

https://www.youtube.com/@thomasneemann5 ... ry=freecad
kisolre
Veteran
Posts: 4164
Joined: Wed Nov 21, 2018 1:13 pm

Re: How to create a polar pattern off axis

Post by kisolre »

Hide Pocket, show Sketch. Create DatumLine, map it to the circular edge of Sketch, mode Axis of Curvature. Create Polarpattern, for axis select "Select reference" and select that DatumLine.
Attachments
test_kiss.FCStd
(17.78 KiB) Downloaded 12 times
domad
Veteran
Posts: 2053
Joined: Mon Jun 22, 2020 12:16 pm

Re: How to create a polar pattern off axis

Post by domad »

PunyTune wrote: Fri Jan 21, 2022 6:05 am ...
Hi PunyTune, hello to the community!
You could create a reference (line) that will serve you to create a datum-line that will become the polar axis of the series.
In the example also the one with the axis inclined by 30 °.
Attachments
test.FCStd
(152.79 KiB) Downloaded 20 times
off-center_polar_pattern.png
off-center_polar_pattern.png (240.91 KiB) Viewed 1151 times
PunyTune
Posts: 103
Joined: Sun Jan 06, 2019 1:59 am

Re: How to create a polar pattern off axis

Post by PunyTune »

Thank you all. I have never used a datum line before. This seems simple enough. BUT ....

After creating the compound shape, when I change the attachment position of the disk pad, the polar pattern does not move with it. How can I create a compound shape that I can move around?

And, in the test file sent by Domad, if I try to change the attachment position of his examples, they don't move and the sketch and pad seem to break. His shapes are different than mine. (I don't know what the CopyLine is for.)
kisolre
Veteran
Posts: 4164
Joined: Wed Nov 21, 2018 1:13 pm

Re: How to create a polar pattern off axis

Post by kisolre »

PunyTune wrote: Fri Jan 21, 2022 8:13 pm when I change the attachment position of the disk pad,
You should provide an updated file or more complete explanation what are you actually doing , preferably with steps to reproduce. In my file for example if you move the disc by changing attachment of the Pad sketch or just changing the circle location the polar pattern center should follow since the datumline is attached to the sketch. But since the holes are not attached to the datumline, but to a baseplane the hole pattern will not keep its radius.
User avatar
Shalmeneser
Veteran
Posts: 9475
Joined: Wed Dec 23, 2020 12:04 am
Location: Fr

Re: How to create a polar pattern off axis

Post by Shalmeneser »

You can draw a line in a solitary sketch then attach your datumplane to this line.
domad
Veteran
Posts: 2053
Joined: Mon Jun 22, 2020 12:16 pm

Re: How to create a polar pattern off axis

Post by domad »

PunyTune wrote: Fri Jan 21, 2022 8:13 pm .....
in the test file sent by Domad, if I try to change the attachment position of his examples, they don't move and the sketch and pad seem to break. His shapes are different than mine. (I don't know what the CopyLine is for.)
Hi PunyTune, hello to the community!
As anticipated by @Shalmeneser above, the "CopyLine" (shape binder) was created automatically because a "Datum Line" was created (reference to create the "customized" "polar pattern") using the construction line as a basis located inside the "Construction" folder.
Now to make sure that the "polar pattern" can be moved, without altering the polar rotation radius, it is necessary to intervene in the "sketch001" which determines the "Pocket" to create the hole.
Open the "sketch001" and create an external reference (icon representing a "press") on the vertex of the "Datum Line" and insert a "distance constraint" and a "radius constraint" or a "diameter constraint", to define the size of the hole, this will complete the sketch.
If desired, you can remove the "point onto object" constraint and replace it with an alignment lane (vertical or horizontal) with the center of the circumference that generates the hole.
Now select "CopyLine" and move it, you will see that the "polar pattern" will move without any alteration of the polar rotation radius.
In I am attaching the file with the described modification.
Attachments
Box.FCStd
(240.08 KiB) Downloaded 17 times
Post Reply