Parallel Arcs Sketcher to Part Design Problem

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Gray Area
Posts: 20
Joined: Sat Nov 03, 2018 9:41 pm

Parallel Arcs Sketcher to Part Design Problem

Postby Gray Area » Sun Mar 03, 2019 6:21 am

When I close a sketch of a part that includes parallel arcs, I can not bring that part up on the Part Design Workbench is anything other than Sketcher mode.

When I close Sketcher, while in Part Design, the part completely disappears. As the part is fully constrained, I am mystified as to why this is happening.

I have moved sketches of simple polygons from Sketcher to Part Design for extrusion with no problems, so I think I know the steps involved.

Any help with this problem will be appreciated.

Thank you.

Gary Area


OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13528 (Git)
Build type: Release
Branch: releases/FreeCAD-0-17
Hash: 5c3f7bf8ec51e2c7187789f7edba71a7aa82a88b
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/UnitedStates (en_US)
Attachments
Parallel Arcs.PNG
Parallel Arcs.PNG (24.88 KiB) Viewed 328 times
chrisb
Posts: 19731
Joined: Tue Mar 17, 2015 9:14 am

Re: Parallel Arcs Sketcher to Part Design Problem

Postby chrisb » Sun Mar 03, 2019 6:53 am

Hi Gary, welcome to the forum.
I guess that you have toggled visibility of your sketch. Select it in the tree and hit the space key.
chrisb
Posts: 19731
Joined: Tue Mar 17, 2015 9:14 am

Re: Parallel Arcs Sketcher to Part Design Problem

Postby chrisb » Sun Mar 03, 2019 6:55 am

Besides, if the centers of the arcs are coincident, then one of your 0.125 measures and one of the radiuses are redundant and should be omitted. Redundant constraints usually lead to problems in later steps.
freedman
Posts: 1048
Joined: Thu Mar 22, 2018 3:02 am
Location: Washington State, USA

Re: Parallel Arcs Sketcher to Part Design Problem

Postby freedman » Sun Mar 03, 2019 7:05 am

Besides, one of your 0.125 measures seems to be redundant and should be omitted.
I think both of the .125 dims are redundant, I'm pretty sure the arc dim will constrain the straight sections.
Gray Area
Posts: 20
Joined: Sat Nov 03, 2018 9:41 pm

Re: Parallel Arcs Sketcher to Part Design Problem

Postby Gray Area » Sun Mar 03, 2019 7:18 am

chrisb wrote:
Sun Mar 03, 2019 6:53 am
Hi Gary, welcome to the forum.
I guess that you have toggled visibility of your sketch. Select it in the tree and hit the space key.
Thank you for your reply.

I have tried that, and every other view command I could find. Nothing works.
Gray Area
Posts: 20
Joined: Sat Nov 03, 2018 9:41 pm

Re: Parallel Arcs Sketcher to Part Design Problem

Postby Gray Area » Sun Mar 03, 2019 7:21 am

chrisb wrote:
Sun Mar 03, 2019 6:55 am
Besides, if the centers of the arcs are coincident, then one of your 0.125 measures and one of the radiuses are redundant and should be omitted. Redundant constraints usually lead to problems in later steps.
Thank you for the reply.

If I remove either one of the radius constraints, the part can not be constrained.
Gray Area
Posts: 20
Joined: Sat Nov 03, 2018 9:41 pm

Re: Parallel Arcs Sketcher to Part Design Problem

Postby Gray Area » Sun Mar 03, 2019 7:23 am

freedman wrote:
Sun Mar 03, 2019 7:05 am
Besides, one of your 0.125 measures seems to be redundant and should be omitted.
I think both of the .125 dims are redundant, I'm pretty sure the arc dim will constrain the straight sections.
Thank you for your reply.

I tried removing those measurements one at a time. If I remove either one, the part can not be constrained.
chrisb
Posts: 19731
Joined: Tue Mar 17, 2015 9:14 am

Re: Parallel Arcs Sketcher to Part Design Problem

Postby chrisb » Sun Mar 03, 2019 7:32 am

You can upload your file for further inspection. As for the constraints, did you add the coincidence constraint on the centers of the arcs mentioned above?
Gray Area
Posts: 20
Joined: Sat Nov 03, 2018 9:41 pm

Re: Parallel Arcs Sketcher to Part Design Problem

Postby Gray Area » Sun Mar 03, 2019 8:42 am

chrisb wrote:
Sun Mar 03, 2019 7:32 am
You can upload your file for further inspection. As for the constraints, did you add the coincidence constraint on the centers of the arcs mentioned above?
No. I did attempt to do that at one point, but it was not possible to do so.

I have attached my file to this reply.

Thank you, again, for your help in solving this problem.

Gray Area
Attachments
Test Arcs.FCStd
(5.98 KiB) Downloaded 14 times
kisolre
Posts: 1361
Joined: Wed Nov 21, 2018 1:13 pm

Re: Parallel Arcs Sketcher to Part Design Problem

Postby kisolre » Sun Mar 03, 2019 9:05 am

As ChrisB already mentioned in the first post - your sketch is hidden:
SketchHidden.PNG
SketchHidden.PNG (48.43 KiB) Viewed 302 times
Toggling visibility by either selecting it from the tree and pressing "space" or LMB over it/Toggle visibility will show it:
SketchVisible.PNG
SketchVisible.PNG (47.73 KiB) Viewed 302 times
Notice the black color of the name when visible and gray when hidden.

Also your sketch is overconstrained:
Overconstrained.PNG
Overconstrained.PNG (115.33 KiB) Viewed 302 times
Since centers of are not constrained "coincident" they only appear to be on top of each other but do not depend from each other. Here is one of the proper constraining variations:
Constrained.PNG
Constrained.PNG (104.4 KiB) Viewed 302 times