Bad dependency in PartDesign Revolution

[FrViPofm]

Bur reported at :
https://freecadweb.org/tracker/view.php?id=3156

Steps :
1. New document
2. New body
3. New sketch "Small" (e.g. XY plane)
4. Draw a circle ( r10 mm) at 20 mm from Y
6. Close the sketch "Small"
7. make a revolution from this sketch
The result is a torus
8. Unselect the sketch
9. New sketch "Big" (e.g. XZ plane)
10. Draw a circle ( r20 ) at 60 mm from Z
11. Close "Big"
12. Make a revolution from this sketch (with "vertical axis" or "Z axix")
The result should be a second torus.
But I get the same first torus.

13. Delete "Revolution" from "Small"
The result is as expected for the "Big" torus.

The dependency graph shows that the second revolution depends on the first, that would not be.

Creating a second body for the second torus seems to avoid the bug.

The bug has been found during a try of the tuto :
https://www.youtube.com/watch?v=yo79c2gm0pc

The test as been made several times.
The problem has not been found on FC 0.16.
The problem exists on FC 0.17.11751 (pub date : 2017/08/10) (OS as below)
And it seems that in the tuto (see above) , Paul Randall is using a FC 0.17 and doesn't have this bug

File and picture on the bug report.

OS: Ubuntu 16.04.2 LTS 64-bit
Version of FreeCAD : 0.16.6712 (Git) 64-bit
Build type: None
Branch: releases/FreeCAD-0-16
Python : 2.7.12
Qt : 4.8.7
Coin : 4.0.0a
OCC : 6.8.0.oce-0.17

[ickby]

From the description this seems not to be a bug. Part Design allows for a single solid only. Whenever you create seperated solids some get removed so that there is only one left. The bug was the behaviour in 0.16 as it should have done this too.

[Kunda1]

From the description this seems not to be a bug. Part Design allows for a single solid only. Whenever you create seperated solids some get removed so that there is only one left. The bug was the behaviour in 0.16 as it should have done this too.

Oy vey, lots of re-educating needs to happen now because people are seeing this as correct behavior in 0.16 tutorials:

The bug has been found during a try of the tuto :
https://www.youtube.com/watch?v=yo79c2gm0pc

[prandall]

Hello All,

I have just now found this post and wanted to address the concerns. I am the author of the tutorial linked here and am willing to make sure I do not facilitate undesired understanding of FreeCAD.

I am trying to create tutorials while I am still new to various concepts on FreeCAD as personally I lose touch with what is causing confusion when I get familiar with a subject. I imagine this is true for most, so when I gain understanding on something I try to record it at that time so it is closer to what a new user is experiencing.

I would love to update the description with the problem as I now understand.

It seems that the desired work-flow in Part Design is to create a single contiguous object in each Body container. Multiple contiguous bodies can make up a part.

In some versions of FreeCAD I have been able to create multiple non-contiguous objects from a single sketch. I am now understanding that this is undesirable.

The video linked was one of my first and is of fairly poor quality I would also being willing to re-record and replace. But I only would do that if I have a better understanding.

I have read some of the various posts on best practices and other subjects. But I am far from having a full understanding of FreeCAD at this point, and I have terrible memory. If there is an obvious post that I am missing I would not mind at all spending the time reading.

Let me know if my description of the issue is accurate.

Paul Randall


P.S. My apologies to Kunda1, I do not want to create trouble for anyone, I would love to work to correct any of my in-accuracies.

Oy vey, lots of re-educating needs to happen now because people are seeing this as correct behavior in 0.16 tutorials:

[chrisb]

I think you described the current situation correctly. As there are several tutorials for 0.16 out there, I think there is no need for another one. If you want to rerecord something it would be great if you get accustomed with the upcoming 0.17 and make a beginner's video!

[prandall]

Thaks chrisb, my tutorial is actually .17, I will add an update to the description for now. I will also try to think if I can make a good beginners video.