misplaced clones

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freman
Posts: 602
Joined: Tue Nov 27, 2018 10:30 pm

misplaced clones

Postby freman » Sat Oct 12, 2019 8:30 pm

Hi,

I have a part which I wish to clone to cut multiple copies from a piece of stock.

I just created a clone and it was offset from the original. I originally thought this was intentional to make it easier to distinguish them, however I see that the placement of the clone is 0,0,0.

I moved the clone to y+53 which is where I need it but have an offset in X which is not desired. I think the origin of this offset is because I moved the origin in Body after I had made. I originally had x=0 on the top of the mounting flange. This was not very practical so I moved it to the lower face.

It seems that in creating the clone it has been placed with the upper face at the new x=0 aligning it with the lower face of the original.

Is this a bug or a feature? How can I align them correctly?

TIA.

OS: Linux (LXDE/LXDE)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.17672 (Git)
Build type: Unknown
Branch: (HEAD detached at ffb4aa5dc)
Hash: ffb4aa5dcfc0f0b6fb37161fd1c820ade167eb04
Python version: 2.7.16
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedKingdom (en_GB)
Attachments
clones.FCStd
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Last edited by freman on Sat Oct 12, 2019 9:31 pm, edited 1 time in total.
chrisb
Posts: 18137
Joined: Tue Mar 17, 2015 9:14 am

Re: misplaced clones

Postby chrisb » Sat Oct 12, 2019 9:20 pm

Can you upload the file? It is difficult to imagine what exactly you are talking about.
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freman
Posts: 602
Joined: Tue Nov 27, 2018 10:30 pm

Re: misplaced clones

Postby freman » Sat Oct 12, 2019 9:31 pm

My apologies, I thought I had done. Just added to OP.
chrisb
Posts: 18137
Joined: Tue Mar 17, 2015 9:14 am

Re: misplaced clones

Postby chrisb » Sat Oct 12, 2019 10:23 pm

You probably used the clone from PartDesign workbench. I have to admit that have not yet fully understood how that is supposed to be used. It is not the body which has the same placement as the clone source, but the contained BaseFeature.

If you want just a copy of the body, then use Draft->Clone (blue sheep) and you will get a clone with the same coordinates as the body.
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freman
Posts: 602
Joined: Tue Nov 27, 2018 10:30 pm

Re: misplaced clones

Postby freman » Sun Oct 13, 2019 8:01 am

Thanks for the explanation Chris, I would never have worked that out. If the reference object is the BaseFeature then it should be placed at the same position as the BaseFeature of the original.

This looks like an oversight when this was designed where someone assumed the perhaps trivially typical situation where the BaseFeature is centred at the coordinate origin. Unless someone can explain a use for this nuanced difference, I may open a bug report.

The whole concept of a clone is something which is identical in every respect.
chrisb
Posts: 18137
Joined: Tue Mar 17, 2015 9:14 am

Re: misplaced clones

Postby chrisb » Sun Oct 13, 2019 9:23 am

freman wrote:
Sun Oct 13, 2019 8:01 am
This looks like an oversight when this was designed where someone assumed the perhaps trivially typical situation where the BaseFeature is centred at the coordinate origin.
This was discussed when 0.17 was developed with the ShapeBinders - and I had the same view as you have.

The idea of placing BaseFeatures in the origin follows the use case of a 4 cylinder engine, where you create a piston once and then have multiple instances. Each of them has to be placed relative to the origin, and not to some other piston.

While ShapeBinders got later the additional property "TraceSupport" the BaseFeature didn't. But it would make a nice feature request. Maybe there is already one.