How to break an array of a pad into its parts?

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berupp
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Joined: Wed Oct 29, 2014 8:03 pm

How to break an array of a pad into its parts?

Post by berupp »

Hi everyone

What I want to achieve:
I created a sketch and turned it into a pad, afterwards I created an array with 6 elements.
I then placed an irregular shaped object inside so I can cut it from the pad array.
freccad.png
freccad.png (216.96 KiB) Viewed 3691 times
Now I want to basically print out each part of the array and use it as template for some old fashioned jigsaw work.

How can I achieve that last step? Do I have to ditch the array and copy/position each pad by hand in order to rearrange it after the cut?

Edit:So FreeCAD is not happy with me trying to cut from the array so I guess I will copy the pads, if someone has a cool
way to do this more elegantly let me know


Thanks guys, I just started using FreeCAD and it is fascinating.
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quick61
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Re: How to break an array of a pad into its parts?

Post by quick61 »

berupp wrote:Hi everyone

What I want to achieve:
I created a sketch and turned it into a pad, afterwards I created an array with 6 elements.
I then placed an irregular shaped object inside so I can cut it from the pad array.
OK in theory, but your going to have trouble with coincident, A.K.A., coplanar faces. There needs to be a little space between the elements of the Array. So if your part is 6 mm high, there should be a Z interval of 6.001 mm or however many decimal places you have configured. Once you have some spacing there, yes,make the Cut(s).
Now I want to basically print out each part of the array and use it as template for some old fashioned jigsaw work.

How can I achieve that last step? Do I have to ditch the array and copy/position each pad by hand in order to rearrange it after the cut?

Thanks guys, I just started using FreeCAD and it is fascinating.
Once you have all your cuts made, Go back to the Draft Workbench and use Draft > Downgrade and you should end up with all your separate solids. The Draft Downgrade will explode your result into the next basic shapes down from the Cut.
Exploded_Array.png
Exploded_Array.png (130.16 KiB) Viewed 3677 times
Mark
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quick61
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Re: How to break an array of a pad into its parts?

Post by quick61 »

Edit:So FreeCAD is not happy with me trying to cut from the array so I guess I will copy the pads, if someone has a cool
way to do this more elegantly let me know
Did you provide a little space between your intervals like I mentioned. If you did not, it will fail because the Array can not have coincident faces and then be expected to perform in any further Boolean operations.

Oh, and Welcome to FreeCAD and the Forum. ;)

Mark
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quick61
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Re: How to break an array of a pad into its parts?

Post by quick61 »

Also, if you would attach your file, we could tell you just where things are going wrong. The forum will accept .FCstd files, so no need to zip them.

Mark
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berupp
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Re: How to break an array of a pad into its parts?

Post by berupp »

Thank you so much Mark

I watched your youtube video: From FreeCAD to the real world. Great video. Now I want a SmartTrap too :)

By now I copied the pads but the `Downgrade`function was exactly what I was looking for.

I do however have a little trouble exporting as flattened SVG. For some reason I am missing a few pixels at the corners.
test.svg
(16.18 KiB) Downloaded 143 times
Any idea how I can fix thisÉ I`m so close
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quick61
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Re: How to break an array of a pad into its parts?

Post by quick61 »

If you attach your original file I will be able to have a look and see what your exact problem is. Barring that, I would recommend taking the part your wanting to export to Flattened SVG into the Draft Workbench and make a 2D Shape View (Draft Shape2DView) of the part(s) and export them to the Flattened SVG. Given your after templates, this would be the best and cleanest way to export as it will only export the outline without any faces. This is what I always do when I use Flattened SVG for CAM / CNC work.

Mark
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berupp
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Re: How to break an array of a pad into its parts?

Post by berupp »

So I had some time to play with my model today and followed the steps as suggested, just to try that workflow, and it worked like a charm.

I still have the problem with the export though.
As suggested I created a Shape2DView of the downgraded array and exported it as a flattened SVG, The corners are still cut off.

I noticed that the size of the SVG is always the same (in my case 430x318) and it doesn't change when I resize my sketch. So if I make the object larger the export cuts off more of my corners

So there seems to be some overall size property of the sketch that I'm missing.

I attached the file

Thanks for the help
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raspberrypi_case.fcstd
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quick61
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Re: How to break an array of a pad into its parts?

Post by quick61 »

This is strange. You haven't posted your Help > About FreeCAD info so I can only guess if your using the latest version, but when exporting the Shape2DView to flattened SVG it should be sizing the SVG to the bounding box, not some set X/Y size. What are you using to view your SVG file once it is exported? Are you viewing in FreeCAD or some external program?

Or maybe your using FreeCAD and opening as Drawing, which does seem to cut off the edges. (this I don't think should do that). Try opening your file in an external program like Inkscape or open as geometry with FreeCAD and see if it's cut off. Opening as Drawing in FreeCAD might need some looking into....

Mark
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berupp
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Re: How to break an array of a pad into its parts?

Post by berupp »

OS: Windows 7
Word size: 32-bit
Version: 0.14.3700 (Git)
Branch: releases/FreeCAD-0-14
Hash: 32f5aae0a64333ec8d5d160dbc46e690510c8fe1
Python version: 2.6.2
Qt version: 4.5.2
Coin version: 3.1.0
SoQt version: 1.4.1
OCC version: 6.5.1
I will try the export at home on Ubuntu. I opened the SVG in Gimp2, Firefox as well as FreeCAD as drawing with the same results.
Opening the SVG in FreeCAD as geometry is working fine.
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quick61
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Re: How to break an array of a pad into its parts?

Post by quick61 »

OK, I just opened one of the exports in Inkscape, and indeed the page size is smaller than the shape. I'm about to call this a bug. It seems it is missing part of the Arcs. As a test I placed a rectangle around the outer parameter and exported again and it comes out right. If you don't mind, I'll include one of your Shape2DView files as an example for the Bug report.

Mark
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