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 279 times
Haut_sv3.FCStd
(29.7 KiB) Downloaded 6 times
User avatar
dcapeletti
Posts: 383
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 2 times
revolution.png
revolution.png (108.34 KiB) Viewed 274 times
construction mode.png
construction mode.png (106.09 KiB) Viewed 274 times
freecad.png
freecad.png (77.83 KiB) Viewed 274 times
chrisb
Posts: 18137
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 6 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 5 times
chrisb
Posts: 18137
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: 1060
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]
chrisb
Posts: 18137
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,