OBELISK

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pekkio
Posts: 21
Joined: Wed Jun 14, 2017 2:39 pm

OBELISK

Postby pekkio » Sat Sep 02, 2017 10:00 am

Hi to everyone and thank you for your time. How can I obtain an obelisk by creating a pocket on two faces of a parallelepiped, but not obtaining what I have on my screenshot? :(
I am quite sure there is a problem of dependency and probably I should use other systems such as loft for example.
Please your help will be really appreciated !!!

OS: Mac OS X
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.6712 (Git)
Build type: Release
Branch: releases/FreeCAD-0-16
Hash: da2d364457257a7a8c6fb2137cea12c45becd71a
Python version: 2.7.11
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17
screenshot.png
screenshot.png (181.31 KiB) Viewed 881 times
obelisco.FCStd
(13.44 KiB) Downloaded 16 times
ulrich1a
Posts: 1881
Joined: Sun Jul 07, 2013 12:08 pm

Re: OBELISK

Postby ulrich1a » Sat Sep 02, 2017 12:38 pm

The approach in FreeCAD 0.16 will be a helper pad. This allows to attach the pocket sketch to the right place. The helper pad will be than removed by the pocketing action.

Ulrich
Attachments
obelisco_helper_pad.fcstd
(25.9 KiB) Downloaded 14 times
paullee
Posts: 1753
Joined: Wed May 04, 2016 3:58 pm

Re: OBELISK

Postby paullee » Sat Sep 02, 2017 1:48 pm

A good exercise for practising FC for myself also!

Alternative approach with 2 sketches + expressions in spreadsheet, so the form can update according to input in the spreadsheet field.

Hope other have another approach to learn more :)

Screenshot from 2017-09-02 21-40-04.png
Screenshot from 2017-09-02 21-40-04.png (139.13 KiB) Viewed 843 times
Screenshot from 2017-09-02 21-40-10.png
Screenshot from 2017-09-02 21-40-10.png (158.23 KiB) Viewed 843 times
In fact, the mathematical formula (almost forgotten since high school) take me more time, and NormandC's hint below help the top part.
https://forum.freecadweb.org/viewtopic.php?t=4230
ulrich1a
Posts: 1881
Joined: Sun Jul 07, 2013 12:08 pm

Re: OBELISK

Postby ulrich1a » Sat Sep 02, 2017 2:26 pm

paullee wrote:
Sat Sep 02, 2017 1:48 pm
Hope other have another approach to learn more
Here you go. My favorite approach for such parts is the draft clone method.
1. Make a side-view sketch of the part.
2. Pad the sketch symmetrically in the Part-Design-Workbench (Be sure to pad it big enough.)
3. Create a Draft-Clone of the Pad.
4. Rotate the Clone by 90° with the Placement. (You have to choose the correct axis!)
5. Make a common of both in the Part-Workbench.

Ulrich
Attachments
obelisco_draft_clone.fcstd
(10.65 KiB) Downloaded 15 times
paullee
Posts: 1753
Joined: Wed May 04, 2016 3:58 pm

Re: OBELISK

Postby paullee » Sat Sep 02, 2017 3:02 pm

ulrich1a wrote:
Sat Sep 02, 2017 2:26 pm
paullee wrote:
Sat Sep 02, 2017 1:48 pm
Hope other have another approach to learn more
Here you go. My favorite approach for such parts is the draft clone method.
1. Make a side-view sketch of the part.
2. Pad the sketch symmetrically in the Part-Design-Workbench (Be sure to pad it big enough.)
3. Create a Draft-Clone of the Pad.
4. Rotate the Clone by 90° with the Placement. (You have to choose the correct axis!)
5. Make a common of both in the Part-Workbench.

Ulrich
Apparently this is a cleaner method! Thank for sharing!
renatorivo
Posts: 2225
Joined: Tue Feb 21, 2012 8:07 pm
Location: Torino - Italy

Re: OBELISK

Postby renatorivo » Sat Sep 02, 2017 3:10 pm

Very simple procedure
- Create a Pad with Sketch001
- Cut Pad from Pocket
you can complete with expressions in spreadsheet
obelisco1.png
obelisco1.png (28.18 KiB) Viewed 826 times
obelisco1.FCStd
(22.62 KiB) Downloaded 22 times
Jee-Bee
Posts: 1959
Joined: Tue Jun 16, 2015 10:32 am
Location: Netherlands

Re: OBELISK

Postby Jee-Bee » Sat Sep 02, 2017 6:36 pm

I had some difficulties with loft during creating a obelisk...
I had created 2 sketches but was unable to select the sketches for the loft. When preselecting i get an error!!

OS: Mac OS X
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.11575 (Git)
Build type: Release
Branch: (detached from e3066d1)
Hash: e3066d1424a96ee16845f700154b3f7c8f51bb9f
Python version: 2.7.13
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.1.0
Attachments
Obelisk.FCStd
(14.08 KiB) Downloaded 12 times
Screen Shot 2017-09-02 at 19.02.40.png
Screen Shot 2017-09-02 at 19.02.40.png (22.57 KiB) Viewed 805 times
Screen Shot 2017-09-02 at 19.02.10.png
Screen Shot 2017-09-02 at 19.02.10.png (58.71 KiB) Viewed 805 times
pekkio
Posts: 21
Joined: Wed Jun 14, 2017 2:39 pm

Re: OBELISK

Postby pekkio » Sat Sep 02, 2017 7:54 pm

@renatorivo Brilliant solution, as usual from you.
@bee jee I believe Mac users have some more problems unfortunately. I got crashes from a simple sweep then I passed the file to my friend with WIN 7 and the sweep went fine.
paullee
Posts: 1753
Joined: Wed May 04, 2016 3:58 pm

Re: OBELISK

Postby paullee » Sun Sep 03, 2017 3:30 am

paullee wrote:
Sat Sep 02, 2017 3:02 pm
ulrich1a wrote:
Sat Sep 02, 2017 2:26 pm
paullee wrote:
Sat Sep 02, 2017 1:48 pm
Hope other have another approach to learn more
Here you go. My favorite approach for such parts is the draft clone method.
1. Make a side-view sketch of the part.
2. Pad the sketch symmetrically in the Part-Design-Workbench (Be sure to pad it big enough.)
3. Create a Draft-Clone of the Pad.
4. Rotate the Clone by 90° with the Placement. (You have to choose the correct axis!)
5. Make a common of both in the Part-Workbench.

Ulrich
Apparently this is a cleaner method! Thank for sharing!
Another alternative simply with lofts + 2 sketch + 1 point - as attached.
(All could be 'linked' via spreadsheet)

Now, I am not sure but there should be some criteria/scenarios for choosing between options by Boolean Common of 2 solids or Lofting :)

It may depends on availability of information / design e.g. a section, subsequent ease of modification etc.
Screenshot from 2017-09-03 11-24-04.png
Screenshot from 2017-09-03 11-24-04.png (128.16 KiB) Viewed 767 times
Jee-Bee
Posts: 1959
Joined: Tue Jun 16, 2015 10:32 am
Location: Netherlands

Re: OBELISK

Postby Jee-Bee » Sun Sep 03, 2017 12:16 pm

pekkio wrote:
Sat Sep 02, 2017 7:54 pm
@renatorivo Brilliant solution, as usual from you.
@bee jee I believe Mac users have some more problems unfortunately. I got crashes from a simple sweep then I passed the file to my friend with WIN 7 and the sweep went fine.
In that case i ask on the developer forum.