is Part design WB Thickeness very sensitive?

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Cekuhnen
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is Part design WB Thickeness very sensitive?

Post by Cekuhnen »

not really a complex model
Screen Shot 2021-07-25 at 5.51.26 PM.png
Screen Shot 2021-07-25 at 5.51.26 PM.png (62.28 KiB) Viewed 722 times
Yet FreeCAD fails
Screen Shot 2021-07-25 at 5.51.14 PM.png
Screen Shot 2021-07-25 at 5.51.14 PM.png (163 KiB) Viewed 722 times
Here is a link
https://drive.google.com/open?id=1TslWT ... p=drive_fs
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drmacro
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Re: is Part design WB Thicken very sensitive?

Post by drmacro »

The short answer is yes, Thickness is very sensitive.

It is prone to fail with all but the simplest geometry...and even then.

In your example, it might work if you set Refine = true on the object before applying Thickness.

Sometimes it works inward but not vice versa...sometimes vice versa.
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Re: is Part design WB Thickeness very sensitive?

Post by chrisb »

I'm afraid the top seam is already causing thickness to fail.
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Cekuhnen
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Re: is Part design WB Thickeness very sensitive?

Post by Cekuhnen »

Uff that is bitter
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TheMarkster
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Re: is Part design WB Thickeness very sensitive?

Post by TheMarkster »

The file is a bit messy, but seems to work. I had to remove the mesh object to get the file size down for uploading to the board.

The idea is to begin with an additive sphere, rotated such that the problematic seamline is out of the way, and cut away material in preparation for the thickness. I placed it such that the top of the sphere was coincident with the top of the dome and set the radius to match the dome's radius, which I measured to be about 89.05 mm.
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Modify ArcCut sketch for the first pocket.
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After the pocket:
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And after one more pocket:
Snip macro screenshot-30f98b.png
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Without the seamline the thickness now works.
Snip macro screenshot-c57ee5.png
Snip macro screenshot-c57ee5.png (93.35 KiB) Viewed 662 times
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Cekuhnen
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Re: is Part design WB Thickeness very sensitive?

Post by Cekuhnen »

Very interesting - i was actually asking myself if the seam is an issue - knowing that from the fillet problem I encountered on the glass body.

I started to rebuild this the good old way of doing it in parts but because of how Part Deign WB works it needs to flow so the end result is always one body I can continue working on.

I will try that solid body start idea you showed too.

Thank you for sharing and trying

The thickness command is nearly unusable - it even fails with half a circle revolve into half a dome
Screen Shot 2021-07-25 at 10.49.44 PM.png
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I start getting the feeling that with the lack of some tools like Blend Loft in Part Design or more fillet types and the finicky of tools like thickness limit FreeCADin what I could build with an efficient and clean workflow.

What I find very curious about FreeCAD is how smart some tools are - even the Sketcher solver with the ability to clean up the sketch yet then a sketch offset is missing or midpoint (or did not discover it yet)
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Cekuhnen
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Re: is Part design WB Thickeness very sensitive?

Post by Cekuhnen »

TheMarkster wrote: Mon Jul 26, 2021 2:09 am The file is a bit messy, but seems to work.

here a current result - not too bad the fluid slots are missing and the pipe for the plunger
but your suggestion with the rotation seems to work. edges are nasty here.
also I noticed that intersect check box helps a lot when using grow inside and arc corners.

Screen Shot 2021-07-26 at 12.34.17 AM.png
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Screen Shot 2021-07-26 at 12.34.23 AM.png
Screen Shot 2021-07-26 at 12.34.23 AM.png (63.61 KiB) Viewed 629 times
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Re: is Part design WB Thickeness very sensitive?

Post by M4x »

Nice result!

Regarding your initial problem: I think I'd used rotate and a pocket :)
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Cekuhnen
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Re: is Part design WB Thickeness very sensitive?

Post by Cekuhnen »

M4x wrote: Mon Jul 26, 2021 5:46 am Nice result!

Regarding your initial problem: I think I'd used rotate and a pocket :)
I tried that two with cutting the groove at a position where there is or is not the vertical seam - same issue. The fact that’s half a sphere can break the part design wb thickness command made me quite concerned.

Thickness is a tool I use significantly in my teaching and I can see students being royalty frustrated and lacking the ability to work around it.


I have to test this one more Time since I noticed that the intersect checkbox can help the thickness to work when going to the inside
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Re: is Part design WB Thickeness very sensitive?

Post by M4x »

I tried to propose a solution without using thickness (I never use it by the way ;) ). You can make this thin wall directly if your sketch is created accordingly.
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