Broken body?

Post here for help on using FreeCAD's graphical user interface (GUI).
Forum rules
and Helpful information
IMPORTANT: Please click here and read this first, before asking for help

Also, be nice to others! Read the FreeCAD code of conduct!
kisolre
Veteran
Posts: 4164
Joined: Wed Nov 21, 2018 1:13 pm

Broken body?

Post by kisolre »

Any idea why is this happening? I tried polar pattern 360deg first but that did not solve for more than 2 occurences. So I decided to make copies of the sketch and rotate accordingly performing the cuts but then this happened:
Err.JPG
Err.JPG (120.08 KiB) Viewed 1051 times
Replacing the Cylinder with a padded circle works Ok (AngelBlade_Pad.FCStd).

OS: Windows 8.1
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.15969 (Git)
Build type: Release
Branch: master
Hash: 4765b7e2fe6d3609e9fbf3e3eb6648d7af1dd526
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: Bulgarian/Bulgaria (bg_BG)
Attachments
AngelBlade_Pad.FCStd
(104.52 KiB) Downloaded 23 times
AngelBlade.FCStd
(101.36 KiB) Downloaded 27 times
openBrain
Veteran
Posts: 9034
Joined: Fri Nov 09, 2018 5:38 pm
Contact:

Re: Broken body?

Post by openBrain »

I guess it has something to do with the seam line. Just set "Refine" to "True" in the properties of your Pockets and it should be OK. ;)
openBrain
Veteran
Posts: 9034
Joined: Fri Nov 09, 2018 5:38 pm
Contact:

Re: Broken body?

Post by openBrain »

Also no problem here using a polar pattern of 4 occurrences around base Z axis (at least when Pocket is refined). See attached file. ;)
Attachments
AngelBlade_OB.FCStd
(62.71 KiB) Downloaded 34 times
kisolre
Veteran
Posts: 4164
Joined: Wed Nov 21, 2018 1:13 pm

Re: Broken body?

Post by kisolre »

That fixed it, thanks. But pollar still fails if Vertical sketch axis is selected. It works with Base Z though. Since the sketch is mapped to XZ plane shouldn't 'Vertical sketch axis" = "Base Z axis"?
GeneFC
Veteran
Posts: 5373
Joined: Sat Mar 19, 2016 3:36 pm
Location: Punta Gorda, FL

Re: Broken body?

Post by GeneFC »

Seams can be a problem. Refine can sometimes eliminate the seam problem, as it appears in this case, but not always.

I took your original file and rotated each of the sketch planes by one degree. The correct shape resulted. You might try something similar for the polar-arrayed pocket.

There may be an easy way to rotate the initial cylinder, but since it is not attached I am not sure how that would be done.

In these cases keep in mind that the problem comes from the OCC handling of coincident lines and faces. Only a very tiny adjustment can make things work. A slight change in the sketch, for example, might also work. Specifically, enlarge the lower portion so that it clearly lies outside the cylinder wall.

Gene
openBrain
Veteran
Posts: 9034
Joined: Fri Nov 09, 2018 5:38 pm
Contact:

Re: Broken body?

Post by openBrain »

Actually I never use the sketch-based axis because I found it easier (and more natural) to work with the axis of the body.
But I would have expected the same as you. Maybe it's a bug. ;) Bet that some regulars will give us some relevant information.
kisolre
Veteran
Posts: 4164
Joined: Wed Nov 21, 2018 1:13 pm

Re: Broken body?

Post by kisolre »

I understood about the seams.
But what if you need to design a revolve/groove feature that is away fron the base axis? I make the sketch, move it to where the axis should be, rotate if I have to and then revolve/groove it around sketch axis.
openBrain
Veteran
Posts: 9034
Joined: Fri Nov 09, 2018 5:38 pm
Contact:

Re: Broken body?

Post by openBrain »

kisolre wrote: Wed Feb 27, 2019 4:18 pm But what if you need to design a revolve/groove feature that is away fron the base axis? I make the sketch, move it to where the axis should be, rotate if I have to and then revolve/groove it around sketch axis.
I never do that (moving sketch to align its axis with the rotating axis). It looks complicated to me because you have to manage the absolute positioning of your sketch (vs. its origin) so it matches your need. It can also prevent you to use sketch axis for symmetry/referencing/...
My solution is to draw my sketch as usual, and use a Datum Line as the axis. ;)
chrisb
Veteran
Posts: 53945
Joined: Tue Mar 17, 2015 9:14 am

Re: Broken body?

Post by chrisb »

A recompute of AngleBlade fixes the issue here.

OS: macOS 10.13
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.15525 (Git)
Build type: Release
Branch: master
Hash: 1a7d3d9a37fe43468c8ac84590c1db53e2b2000a
Python version: 3.6.7
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: German/Germany (de_DE)
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
kisolre
Veteran
Posts: 4164
Joined: Wed Nov 21, 2018 1:13 pm

Re: Broken body?

Post by kisolre »

I just made several tests. Each is from reloaded file, mark feature for recompute, recompute:
- file - fixed
- Body - broken
- Origin - broken
- Cylinder - fixed
- Pocket - fixed
- Sketch - fixed
- Pocket001 - broken
- Sketch001 - broken
- Pocket002 - broken
- Sketch002 - broken

This happens every time. There is definitelly something weird happening. Will be nice if some of the devs could look into this - could be some bug lurking underneath.
Post Reply