Hollow Half Sphere/Shell

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Dizzwold
Posts: 3
Joined: Mon Mar 30, 2020 10:51 am

Hollow Half Sphere/Shell

Post by Dizzwold » Mon Mar 30, 2020 11:18 am

Hi
I'm very new to FreeCad. I would like to create a hollow half sphere or shell. My aim once I've created this, is to add it to a solid cylinder to create a dent. If you imagine the cylinder is aluminium and then you hit it with a ball peen hammer, thus a half sphere dent as such. What I've achieved so far is;
Created an ellipsoid
Radius1 4.00mm
Radius2 4.00mm
Radius3 4.00mm
Angle1 90.00˚
Angle2 90.00˚
Angle3 180.00˚
This is great, but how would I go about making this into a shell before I go any further? I maybe going about this the wrong way ‘?’, so any advice would be grateful.
I did create a half sphere another way, in Part I created a sphere, in Draft I Downgrade then Upgrade, but now all I get is a wire when I do this?
After this then I'l look into applying this to a cylinder, but need to read and google some more on this first, to see if I can figure it out for myself.

Regards.

Dizzwold.

I'm running the following;
OS: OS X El Capitan (10.11)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.16146 (Git)
Build type: Release
Branch: (HEAD detached at 0.18.4)
Hash: 980bf9060e28555fecd9e3462f68ca74007b70f8
Python version: 3.6.7
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedKingdom (en_GB)
kisolre
Posts: 2102
Joined: Wed Nov 21, 2018 1:13 pm

Re: Hollow Half Sphere/Shell

Post by kisolre » Mon Mar 30, 2020 12:08 pm

Something like this?
.
Hit Pipe.JPG
Hit Pipe.JPG (75.27 KiB) Viewed 204 times
OS: Windows 8.1 (6.3)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.20276 (Git)
Build type: Release
Branch: master
Hash: 3a0d9e8c514c163be0b750dd75bb4f2afe4f94f1
Python version: 3.6.8
Qt version: 5.12.1
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: Bulgarian/Bulgaria (bg_BG)
Attachments
Hit Pipe.FCStd
(377.71 KiB) Downloaded 7 times
Dizzwold
Posts: 3
Joined: Mon Mar 30, 2020 10:51 am

Re: Hollow Half Sphere/Shell

Post by Dizzwold » Mon Mar 30, 2020 3:35 pm

Hi Kisolre,
Yeah, that's the kind of thing. Thank you for the reply and the screen shot with clues. I've made some progress ‘I think’, using your screenshot as an example. I've got the ellipsoid 4 x 4 x 4mm radius, created a body then 3 sketches with a 3.9mm circle in all 3 axis, but when I select grove I get a dialogue box "Remove axis intersects the sketch". I've obviously not done something correct?

Am I making progress in the right direction?
Attachments
Screen Shot 2020-03-30 at 16.14.36.png
Screen Shot 2020-03-30 at 16.14.36.png (447.94 KiB) Viewed 174 times
Screen Shot 2020-03-30 at 16.29.17.png
Screen Shot 2020-03-30 at 16.29.17.png (466.42 KiB) Viewed 174 times
chrisb
Posts: 24233
Joined: Tue Mar 17, 2015 9:14 am

Re: Hollow Half Sphere/Shell

Post by chrisb » Mon Mar 30, 2020 5:05 pm

When revolving you draw only half of the section, e.g. for a sphere you revolve a half circle.

BTW: Your screenshots would tell more if you show only the relevant portion of it. Usually it is sensible to move contents of 3D view and dialogs to the left near the panels and shoot a small section showing model, messages and relevant parameters.
kisolre
Posts: 2102
Joined: Wed Nov 21, 2018 1:13 pm

Re: Hollow Half Sphere/Shell

Post by kisolre » Mon Mar 30, 2020 6:38 pm

Dizzwold wrote:
Mon Mar 30, 2020 3:35 pm
using your screenshot as an example.
You did notice the attached FreeCAD file at the end of the post, right?
Dizzwold
Posts: 3
Joined: Mon Mar 30, 2020 10:51 am

Re: Hollow Half Sphere/Shell

Post by Dizzwold » Tue Mar 31, 2020 12:18 pm

Hi Kisolre,
Yes I have seen the file. I can create a circle, pad it, and grove it. I can also create a cylinder, thickness it to make a tube, but not with a ellipsoid with 180˚ instead of at 360˚?

Regards.

Dizzwold.
kisolre
Posts: 2102
Joined: Wed Nov 21, 2018 1:13 pm

Re: Hollow Half Sphere/Shell

Post by kisolre » Tue Mar 31, 2020 7:24 pm

Could you please attach what you have so far? I can't understand how you want to use that elipsoid... In you first post the elipsoid you described is actually half sphere. Why not use whole sphere?
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