Basic Attachment Tutorial

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db44022
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Re: Basic Attachment Tutorial

Post by db44022 »

I had some trouble with the Attachment Offset section because my UI did not match the screen shot in the tutorial. I am still not sure why it does not match, I am assuming this is due to the version discrepancy since I am only on 0.18.

It might be good to put a note here for users of older versions so that they do not think there is something wrong....
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2020-12-23_23h15_39.png
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db44022
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Re: Basic Attachment Tutorial

Post by db44022 »

Here is a second discrepency between my project and what is shown in the Tutorial. Did I make a mistake ?
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M4x
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Re: Basic Attachment Tutorial

Post by M4x »

I haven't looked at Bance file and you didn't provide one but I guess that you just padded in one direction and Bance padded symmetrically.
chrisb
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Re: Basic Attachment Tutorial

Post by chrisb »

The tutorial said already that it was made for 0.19, and I think all the fields used are available in 0.18 as well. Nevertheless I have added a note to the tutorial that details may vary.

Concerning the second question: you have missed the advice "tick symmetric to plane".
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steelman
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Re: Basic Attachment Tutorial

Post by steelman »

Thanks for the tutorial. It explains basic ideas and seems quite OK for manipulating sketches, but I am struggling with attachments in slightly different context. I am trying model an angle part (you know, two long flat bars forming an L cross section). Of course there-is-more-than-one-way-to-do-it, for educational purposes I chose to create one box and then use a subtractive box to cut out most of the material. Unfortunately I don't quite get which parts of the subtractive box are being attached to the parts of the body I select.
chrisb
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Re: Basic Attachment Tutorial

Post by chrisb »

steelman wrote: Sat Jan 16, 2021 5:57 pm Unfortunately I don't quite get which parts of the subtractive box are being attached to the parts of the body I select.
Hard to help without the file.
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Bance
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Re: Basic Attachment Tutorial

Post by Bance »

The sketch being attached will be attached at it's origin, the attachment point is defined by the mode and offset.

In the example included, it can be seen that Square is centred on the origin and SmallSquare has it's origin at the bottom left corner.
Enter map mode for SmallSquare, and select in turn the four corners of Square, SmallSquare is always attached by it's origin.
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Example.FCStd
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steelman
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Re: Basic Attachment Tutorial

Post by steelman »

After a fair amount of trial and error and having in mind that everything starts with the attached objects origin, I managed to click the right three vertices and choose the right mode (OZX)

Image
Image

I don't feel like I am in control but at least the job's done (see the attachment).

Final thoughts after work in 0.18. The UI for attachment isn't inherently bad, but it definitely lacks discoverability. A beginner, who like have used FreeCAD for some time, designed a few simple parts and assembled some of them, me has a really hard time figuring out how to control the position and orientation of the attached object. Chrisb's tutorial definitely helped me catching an end of a string to pull further.

I really missed is an indication of position and orientation of the attached object. With these available it would be easier not only to work but to explain each attachment mode with some screenshots on Part_Attachment.

And the last but not least distracting element of the process is that the attached part (subtractive box in my case) doesn't go back to its initial position after removing all references.
ivar-angle.FCStd
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Bance
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Re: Basic Attachment Tutorial

Post by Bance »

Apologies, I misread your post.

After seeing your file, I would make a different suggestion.

First, use an additive primitive to begin, then use a subtractive. Attach the subtractive to the base X axis(this enables offsets), and then use attachment offset to position exactly.
ivar.png
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steelman
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Re: Basic Attachment Tutorial

Post by steelman »

Yes, I tried attachment offsets but I wanted the part to be fully parametric (W,H,L and thickness). Of course, offsets could be formulas. Still, I wanted to attach the subtractive box to the right corner (+Y, +Z) and only adjust its dimensions to produce thickness. Anyway, there is quite some learning ahead of me.

Thanks.
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