90° arc becomes 270° when changing dimensions

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JiPe38
Posts: 123
Joined: Wed Jan 01, 2020 12:41 pm

90° arc becomes 270° when changing dimensions

Postby JiPe38 » Fri Feb 07, 2020 5:42 pm

Hi everybody

I have a design (more or less complicated) in which there is a nylon belt. I use a spreadsheet. To show the interior of the design, I use an "exploding_distance" parameter. When set to 0mm, the assembly of multiple bodies is shown in it's normal configuration. When set to any positive value, it shows the parts exploded.

The attached file, simplified to contain only the belt, contains the value "35 mm" for this explosion parameter. The belt is shown at a position, like extended. No problem. When I set to "0 mm", it can't compute and show the belt in the normal position.

What happens is that, in the sketch, one or two of the arcs, normally 90° angle to joint two lines become 270° angle arcs, which confuses all the sketch and makes it impossible to extrude.

Does this problem come from the way I sketched this belt, or is it a bug ? A strategy to avoid that ?

belt.FCStd
(16.11 KiB) Downloaded 4 times

OS: Windows 10 (10.0)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.19311 (Git)
Build type: Release
Branch: master
Hash: 120b69c74f7dac8c4fa6dbc0a7e10674bde9216c
Python version: 3.7.3
Qt version: 5.12.5
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: French/France (fr_FR)
User avatar
GlouGlou
Posts: 2114
Joined: Sun Apr 05, 2015 9:02 am
Location: La Rochelle, France

Re: 90° arc becomes 270° when changing dimensions

Postby GlouGlou » Fri Feb 07, 2020 6:18 pm

maybe like this.
Attachments
belt.FCStd
(21.49 KiB) Downloaded 6 times
JiPe38
Posts: 123
Joined: Wed Jan 01, 2020 12:41 pm

Re: 90° arc becomes 270° when changing dimensions

Postby JiPe38 » Fri Feb 07, 2020 8:36 pm

Yes it works. Another way of doing this belt. Thanks.
Is this a known issue ?
chrisb
Posts: 24295
Joined: Tue Mar 17, 2015 9:14 am

Re: 90° arc becomes 270° when changing dimensions

Postby chrisb » Sat Feb 08, 2020 9:55 am

JiPe38 wrote:
Fri Feb 07, 2020 8:36 pm
Is this a known issue ?
Yes. It occurs, because "fully constraint" does not mean "unique". It means only, that there is no smooth (=continuous) transition from one solution to another.