Can not use polar function on model

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Andy_1205
Posts: 10
Joined: Mon Aug 12, 2019 8:31 pm

Can not use polar function on model

Postby Andy_1205 » Mon Aug 12, 2019 8:48 pm

Hi

I am relatively new to FreeCad but have succeeded with a few models. I have designed a model for a project I am doing, and all I want to do, is to put 12 x 0.5mm radius holes in a circular pattern on one of the surfaces. I have used the polar function before and thought I understood it!

What I tried was:

1) selected the surface I want the holes on
2) drew a circle 8.0mm radius and padded it to 1.0mm deep
3) I selected the surface of the padded circle and drew one 0.5mm radius circle on it and 'pocketed' it.
4) I then selected the pocketed part to 1.0mm and clicked on the polar option.
This is where I start to get confused:

It placed the second polar copy 180 degrees to the x,y axis point - so the other side of the model in mid air. It did not use the circle it was added to as the shape to follow.

I tried to 'add' the padded circle to the polar function but it would not add any item I selected.

Can someone please excuse my ignorance and explain how I can add a polar function to one part of a larger design? Or do I have t manually add lots of circles??

Many thanks

Andrew
chrisb
Posts: 17585
Joined: Tue Mar 17, 2015 9:14 am

Re: Can not use polar function on model

Postby chrisb » Mon Aug 12, 2019 10:13 pm

You are using PartDesign workbench, right? You can select the axis in the polar pattern dialog.

It would be helpful if you attach the model, and explain with the names used in the model what you want to do.
jmaustpc
Posts: 9558
Joined: Tue Jul 26, 2011 6:28 am
Location: Australia

Re: Can not use polar function on model

Postby jmaustpc » Tue Aug 13, 2019 12:38 am

Andy_1205 wrote:
Mon Aug 12, 2019 8:48 pm
how I can add a polar function to one part of a larger design? Or
It sounds like perhaps you are trying to use a circle for a path to define the polar pattern, if so that is wrong, you define the axis.

Honestly this is well explained in the wiki, search for partdesign workbench, then find the pattern features and read their pages, if still confused then come back here.

Also note that with partdesign pattern tools you can only make patterns on a single solid and not an array of separate solids. For Arrays see Draftwb Array.
Andy_1205
Posts: 10
Joined: Mon Aug 12, 2019 8:31 pm

Re: Can not use polar function on model

Postby Andy_1205 » Tue Aug 13, 2019 7:40 am

Thank you both. I am away from home at moment so can't post the designs but will do as soon as I can.
I will look at the wiki pages - i didn't know they existed so I am sorry!
I am trying to get the polar function to follow a circle which it does when there is only a circle, but I can not seem to get it to do the same when the circle is added to the model. It seems like I would have to do the circle first with the polar changes and then build on that, which can't be right!
I will read the wiki site and come back of still unsure or confused.

Thank you.
jmaustpc
Posts: 9558
Joined: Tue Jul 26, 2011 6:28 am
Location: Australia

Re: Can not use polar function on model

Postby jmaustpc » Tue Aug 13, 2019 5:11 pm

Andy_1205
Posts: 10
Joined: Mon Aug 12, 2019 8:31 pm

Re: Can not use polar function on model

Postby Andy_1205 » Sun Aug 18, 2019 8:51 am

Thank you - to be honest, these did not help much but I found a very helpful post that solved the issue for me:

Re: polar pattern needs a different axis
Postby NormandC » Sat Jun 16, 2018 1:47 am
1. In the Model tree, right-click on Body-roller-clamp and select Toggle active body. The background of Body-roller-clamp should now be light blue to show it's active.
2. Right-click on Pad and select "Set tip". Any new object will now be created immediately below it, rather than at the bottom of the Body tree.
3. Click on 

 Create a new datum line.
4. Select a circular edge of the Body. In the Line parameters, the first button should now be labelled "Circle", and the field next to it should show Pad:Edge4 (the digit may differ depending on which end of the pad you selected).
Under Attachment mode, Axis of curvature should be shown in bold. If it is not, select it.
5. Press OK.
6. Right-click on PolarPattern and select "Set tip" so the tip is set to the last feature again.
7. Double-click on PolarPattern to edit it.
8. In the Axis drop down list, select "Select reference..."
9. Select the datum line in the 3D view.
Press OK.
chrisb
Posts: 17585
Joined: Tue Mar 17, 2015 9:14 am

Re: Can not use polar function on model

Postby chrisb » Sun Aug 18, 2019 9:01 am

jmaustpc wrote:
Tue Aug 13, 2019 5:11 pm
PartDesign_PolarPattern
Andy_1205 wrote:
Sun Aug 18, 2019 8:51 am
Thank you - to be honest, these did not help much but I found a very helpful post that solved the issue for me:
Could you please revisit the above link in the light of your newly acquired knowledge? Please tell us what is unclear, or even better, ask for a wiki account and improve the documentation.

FreeCAD is a community project and here is a first opportunity to give something back.
Andy_1205
Posts: 10
Joined: Mon Aug 12, 2019 8:31 pm

Re: Can not use polar function on model

Postby Andy_1205 » Fri Aug 23, 2019 8:05 am

Chris

I am very new to this forum and how it works, so I am very sorry if my entries have not been complete or as detailed as they should be. I also was not aware I could edit the Wiki entries but will take a look when I have time.

My issue was this - all the tutorials and examples I could find were very clear about how to set up a polar pattern on a single object. What I realise now, is that the single object was based at the axis and so the polar pattern was using that as its reference point.

The issue I had was that I had designed a model for a project I am working on and needed a polar pattern of holes in a specific location on the model and when I tried, the polar option was rotating the initial hole around the origin of the axis and not the centre of the location I wished it to be rotated around.

The solution I found on another forum addressed exactly the issue I was having - it explained I needed to created a datum line and the centre of the circle where I wanted the polar pattern and this was created at 90 degrees to the surface of the circle. Then, I referenced this datum line in the polar pattern settings and immediately, the polar pattern was confined to the correct location.

This issue, and the frustrating one I have encountered where by deleting an object in the tree loses the following items settings has taught me that I need to go back to basics and find a tutorial that explains the way that FreeCad 'thinks' so I can understand more fully. Unfortunately, with 3 kids and a job it is going to take me a while to a) find such a tutorial and b) sit down to read it!

Thank you for taking the time to point out to me these things and please continue to do so. I will do my best to contribute and thank you all for your help so far.

Andrew
chrisb
Posts: 17585
Joined: Tue Mar 17, 2015 9:14 am

Re: Can not use polar function on model

Postby chrisb » Fri Aug 23, 2019 9:33 am

Hi Andrew, good to hear you got it sorted.
I appreciate if people try to solve their problems by themselves, but don't hesitate too long to ask back here. There are many outdated or even bad tutorials out there. If they are on the wiki we'd like to see them improved.