Sphere creation

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Ludovic
Posts: 10
Joined: Thu Aug 08, 2019 8:36 pm

Sphere creation

Postby Ludovic » Thu Aug 08, 2019 9:18 pm

Hello,

I'm quite new to FreeCad...
I'm trying to do a sphere (on the last sketch) and it doesn't work.

I want to do half a revolution (on the vertical axis by the center of the circle) of my last sketch...

I think I don't know how to give it the right axis...

OS: Windows 7
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.16117 (Git)
Build type: Release
Branch: releases/FreeCAD-0-18
Hash: dbb4cc6415bac848a294f03b80f65e888d531742
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: French/France (fr_FR)

If you can help, thank you.

Best regards,
Attachments
err.png
err.png (16.57 KiB) Viewed 405 times
Haut_sv3.FCStd
(29.7 KiB) Downloaded 9 times
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dcapeletti
Posts: 452
Joined: Wed Jul 23, 2014 2:27 pm

Re: Sphere creation

Postby dcapeletti » Thu Aug 08, 2019 9:40 pm

Hey, I've been going over your sketch. You have a line that does not produce a body. I frame it in the image. You can pass that line in build mode.

To create a revolution, you take the sketch and select the axis in which you want the revolution to be made. I attach the new file.

Greetings
Attachments
Haut_sv3.FCStd
(129.65 KiB) Downloaded 10 times
revolution.png
revolution.png (108.34 KiB) Viewed 400 times
construction mode.png
construction mode.png (106.09 KiB) Viewed 400 times
freecad.png
freecad.png (77.83 KiB) Viewed 400 times
chrisb
Posts: 25761
Joined: Tue Mar 17, 2015 9:14 am

Re: Sphere creation

Postby chrisb » Thu Aug 08, 2019 10:27 pm

If you want to create a sphere by a revolution you have to model only half a circle. Otherwise you have so called self intersections.
Ludovic
Posts: 10
Joined: Thu Aug 08, 2019 8:36 pm

Re: Sphere creation

Postby Ludovic » Thu Aug 08, 2019 10:35 pm

Hello,

Thank you very much.
I'm sorry, I didn't explain very well what I'm trying to do.
Let's see the "manual" document.

Best regards,
Attachments
sphere.pdf
(487.96 KiB) Downloaded 10 times
Ludovic
Posts: 10
Joined: Thu Aug 08, 2019 8:36 pm

Re: Sphere creation

Postby Ludovic » Thu Aug 08, 2019 10:50 pm

chrisb wrote:
Thu Aug 08, 2019 10:27 pm
If you want to create a sphere by a revolution you have to model only half a circle. Otherwise you have so called self intersections.
Hello,

Thank you.
I'm sorry, I tried to cut the circle... but it seems it doesn't work.

Best regards
Attachments
Haut_sv3.FCStd
(29.56 KiB) Downloaded 9 times
chrisb
Posts: 25761
Joined: Tue Mar 17, 2015 9:14 am

Re: Sphere creation

Postby chrisb » Thu Aug 08, 2019 11:08 pm

I can have a look at this tomorrow - if nobody else replies.
TheMarkster
Posts: 1728
Joined: Thu Apr 05, 2018 1:53 am

Re: Sphere creation

Postby TheMarkster » Thu Aug 08, 2019 11:57 pm

You need to use an arc instead of a circle if you only want half the sphere. In the video I put the circle into construction mode, then make an arc. The revolve axis is the construction line that was already there.



phpBB [video]
My FreeCAD video series on youtube: https://www.youtube.com/c/mwganson
chrisb
Posts: 25761
Joined: Tue Mar 17, 2015 9:14 am

Re: Sphere creation

Postby chrisb » Fri Aug 09, 2019 5:16 am

There are two more things to say about your model:
- The DatumPlane is unattached, which can make things attached to it unreliable or unpredictable
- The sketch for the sphere contains a 0mm horizontal distance constraint. Use vertical alignment constraint instead. It is in general recommended to prefer geometric constraints over dimensions.
Ludovic
Posts: 10
Joined: Thu Aug 08, 2019 8:36 pm

Re: Sphere creation

Postby Ludovic » Fri Aug 09, 2019 11:27 am

TheMarkster wrote:
Thu Aug 08, 2019 11:57 pm
You need to use an arc instead of a circle if you only want half the sphere. In the video I put the circle into construction mode, then make an arc. The revolve axis is the construction line that was already there.



phpBB [video]
Hello,

Thank you very much.

Best regards
Ludovic
Posts: 10
Joined: Thu Aug 08, 2019 8:36 pm

Re: Sphere creation

Postby Ludovic » Fri Aug 09, 2019 11:35 am

chrisb wrote:
Fri Aug 09, 2019 5:16 am
There are two more things to say about your model:
- The DatumPlane is unattached, which can make things attached to it unreliable or unpredictable
- The sketch for the sphere contains a 0mm horizontal distance constraint. Use vertical alignment constraint instead. It is in general recommended to prefer geometric constraints over dimensions.
Hello,

Thank you, I change the constraint to vertical. I was searching for a better solution, and you gave it to me ;-)

I don't know how to attach the plan...

Best regards,