Polar pattern around datum line

[TopDown]

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.13971 (Git)
Build type: Release
Branch: master
Hash: 8e4dd8ca8496595d4718dc24c872f7ed668b2521
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/Australia (en_AU)

Hi everyone,
I know this topic has been quite active in the forum but I can't seem to make it work.

I want to create a pattern of the pocket (red arrow) following the curve (blue arrow) around a datum line highlighted.
How do I select the datum line to be the centre of the pattern. The pattern will extend around 100 deg. with 19 occurrences.

Thanks for any info,
Gary.

PS. the other pattern was around the normal centrepoint and was no problem.

polar.PNG (15 KiB) Viewed 1138 times

[kisolre]

In the Axis of PolarPatters select "Select reference" and select your Datum Line:

PolarDatumLine.jpg (379.13 KiB) Viewed 1129 times

[TopDown]

Thanks for the quick reply.
Unfortunately "datumline" doesn't show in the selection.

Cheers.

datum.docx

(168.68 KiB) Downloaded 21 times

[TheMarkster]

You select it in the 3d view.

[jmaustpc]

Version: 0.18.13971 (Git)

Your FreeCAD version is obsolete, current 0.18 branch is 3000 commits beyond the version you are using.... see the download page here....

https://github.com/FreeCAD/FreeCAD/releases

[TopDown]

Thanks "TheMarkster".

I felt it was something simple.

Solved.

[kisolre]

Unfortunately "datumline" doesn't show in the selection.

It shows because like TheMarkster pointed out I have it already selected from the 3D view.
I played a little with your file. Because of Topological naming issues try to map your sketches only to basic planes and offset/rotate them to proper position. Use expressions to link to previous feater position. When referencing external geometry use sketches that containt it instead of the resulting features (if possible). Use minimum references need to create what you need.
Here is my result:

[TopDown]

Thanks kisolre,
tips taken in (may not stay there).

Cheers,
Gary.

[TopDown]

I believe this is related to the topic.

Still trying to get my head around the use of datum lines etc.

How do I use the centre point from a construction circle as the centre of my polar array?
I need to create a polar array of the pocket (red arrow) following the curve (blue arrow) using the centre point (black arrow).

Apologies if this is duplicate,
I am gradually getting the idea.

Gary.

polar2.PNG (24.31 KiB) Viewed 1031 times

[kisolre]

You can use named reference dimensions in the sketch and link the datumline position with expressions to that. Or model both parts in one file and use a shapebinder to transfer the datum line to the second part. Or create a mastersketch th the construction geometry as real geometry and use that as reference in next sketches to create the real features.
Again please try to reference the geometry from the sketches that contain it if possible and not from the features created from those sketches. While editing a sketch you can hide the previous feature and show previous sketches by pressing "space" when they are selected in tree view.
In this file I used the first method described above: