unable to make a pocket on a cylindrical surface

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Matael
Posts: 82
Joined: Tue Mar 01, 2016 10:50 pm
Location: France

unable to make a pocket on a cylindrical surface

Post by Matael »

Hi, here is a file where i can't make a pocket in the cylindrical face.
I take car to remove all tangents and superposed lines, but the result is still ugly and not usable

Does anyone have an idea or tip?

Thank's by advance,
Matael


OS: Ubuntu 16.04.3 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13208 (Git)
Build type: Unknown
Branch: master
Hash: 1402e39ba0393d309f372f490ec77f1015be1c1a
Python version: 2.7.12
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17
Locale: English/UnitedStates (en_US)
Attachments
approche_2.fcstd
(438.1 KiB) Downloaded 67 times
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Willem
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Joined: Fri Aug 12, 2016 3:27 pm
Location: Lisse, The Netherlands

Re: unable to make a pocket on a cylindrical surface

Post by Willem »

Hi, you can define a datum plane. Make a sketch on the plane and then make a pocket. The sketch does not need contact with the cylindrical surface to make the pocket succeed
Schermafdruk van 2018-02-22 17-31-10.png
Schermafdruk van 2018-02-22 17-31-10.png (229.26 KiB) Viewed 2008 times
Matael
Posts: 82
Joined: Tue Mar 01, 2016 10:50 pm
Location: France

Re: unable to make a pocket on a cylindrical surface

Post by Matael »

Hi! I think I wasn't clear enough. What make me unhappy is the result of the last pocket:
2018-02-23-103407_605x490_scrot.png
2018-02-23-103407_605x490_scrot.png (23.36 KiB) Viewed 1936 times
which is quite ugly, and sometimes put the piece in black. And I would like to have something as clean as you

here an other "bug" in the result:
2018-02-23-103642_964x659_scrot.png
2018-02-23-103642_964x659_scrot.png (45.63 KiB) Viewed 1936 times
As you can see, the left side wasn't "pocketed". Do you use a particular solver or options?

BTW, thx for the tip. It wasn't what I was looking for ATM, but I was searching for it a long time ago \o/
chrisb
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Joined: Tue Mar 17, 2015 9:14 am

Re: unable to make a pocket on a cylindrical surface

Post by chrisb »

There is a problem some steps before: If you do a Check Geometry you find lots of errors, first introduced with Pocket004.
I reworked the constraints and now it works until the end.
Attachments
approche_2_cb.fcstd
(183.67 KiB) Downloaded 65 times
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
Matael
Posts: 82
Joined: Tue Mar 01, 2016 10:50 pm
Location: France

Re: unable to make a pocket on a cylindrical surface

Post by Matael »

Great!
Thank you @chrisb!

I have some questions for you about the "check geometry" tool:
1)when do you use it? (always? just when your part have some bugs? else?)
2)Is this tool only available in the Part WB?
3) how did you see that the firtissue was introduced at pocket 4? I tried to run the check geometry, but it only find errors at the last steps.
chrisb
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Re: unable to make a pocket on a cylindrical surface

Post by chrisb »

Matael wrote: Fri Feb 23, 2018 10:52 am I have some questions for you about the "check geometry" tool:
1)when do you use it? (always? just when your part have some bugs? else?)
2)Is this tool only available in the Part WB?
3) how did you see that the firtissue was introduced at pocket 4? I tried to run the check geometry, but it only find errors at the last steps.
You're welcome.

1) I use Check Geometry when an error occurs. I have set in Prefererences->PartDesign->General->Automatically Check Model checked.
2) This tool is available in Part WB and can be applied to all objects. You can create a customized toolbar to make it available in other WBs
3) I checked all intermediate states until I found one, that shows an error and the previous does not. To make a more intensive checking you have to enable BOPCheck: https://www.freecadweb.org/wiki/index.p ... ckGeometry.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
Matael
Posts: 82
Joined: Tue Mar 01, 2016 10:50 pm
Location: France

Re: unable to make a pocket on a cylindrical surface

Post by Matael »

@chrisb

I've got 2 other problems, about the same project:

1) There is a problem with Pocket 005 wich seems to not be connected, but, as there is a line and a arc of circle, and I already have 2 coincident constraints, I can't see why I have the message "wire not closed". More :

2)Before I tried to mak a mirror of the last feature, there weren't bug (I think). Have you already experimented the situation where a new feature affects the validity of previous steps?

the file:
https://drive.google.com/open?id=1Zbxta ... S-1chmlt_O

(I don't know how to share it else, it's to big to be attached in this post)

PS: I know the design is quite ugly, but I'm doing it on the fly
chrisb
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Re: unable to make a pocket on a cylindrical surface

Post by chrisb »

I guess both problems have the same reason: You used careless the block constraint in Sketch005. If you delete the block constraint you can see that the corner is not connected, which it must be for the subsequent steps.
After you have repaired that you have to check if the rest of your model is ok because most probably the nembering of faces and edges has changed.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
Matael
Posts: 82
Joined: Tue Mar 01, 2016 10:50 pm
Location: France

Re: unable to make a pocket on a cylindrical surface

Post by Matael »

Ok thank's for you're help, I will improve the way is designed that, I think it will reduce the errors
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