Intersecting pockets

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earthcare
Posts: 26
Joined: Tue May 31, 2016 7:46 am
Location: Australia

Intersecting pockets

Postby earthcare » Wed Sep 05, 2018 2:00 am

Hi

I'm trying to create a right-angle water feed attachment for 3D prototype printing; I've created the housing shape, and added the two sketches for the actual passage through it. (attached)

But to simply pocket the two sketches by the right amount will result in the corner part of the housing having lots of holes - hardly the point. I have no idea how to make these two sketches intersect properly.

Help, please! :? :oops:

Edwin

OS: Linux Mint 18.3
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13522 (Git) AppImage
Build type: None
Branch: releases/FreeCAD-0-17
Hash: 3bb5ff4e70c0c526f2d9dd69b1004155b2f527f2
Python version: 2.7.6
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/Australia (en_AU)
Attachments
RevD-L.fcstd
(87.24 KiB) Downloaded 11 times
Last edited by earthcare on Thu Sep 06, 2018 1:18 am, edited 1 time in total.
TheMarkster
Posts: 1201
Joined: Thu Apr 05, 2018 1:53 am

Re: Intersecting pockets

Postby TheMarkster » Wed Sep 05, 2018 3:50 am

You can use a subtractive pipe/sweep to connect the 2 holes together. Just need to draw a path (arc) to connect them.

phpBB [video]
My FreeCAD video series on youtube: https://www.youtube.com/playlist?list=P ... GEBlLshYGa
earthcare
Posts: 26
Joined: Tue May 31, 2016 7:46 am
Location: Australia

Re: Intersecting pockets

Postby earthcare » Thu Sep 06, 2018 1:07 am

Hi TheMarkster

I'm sorry, I don't see what you're doing here.
Bance
Posts: 281
Joined: Wed Feb 11, 2015 3:00 pm
Location: London

Re: Intersecting pockets

Postby Bance » Thu Sep 06, 2018 1:31 am

The wiki page for subtractive pipe/sweep is here....

https://www.freecadweb.org/wiki/PartDes ... activePipe

Essentially, what it does is, use your sketch to move along a path and remove the material it passes through.

There is an additive version as well, which you might have used for the shell of your object.

HTH Steve.
TheMarkster
Posts: 1201
Joined: Thu Apr 05, 2018 1:53 am

Re: Intersecting pockets

Postby TheMarkster » Thu Sep 06, 2018 6:57 pm

earthcare wrote:
Thu Sep 06, 2018 1:07 am
Hi TheMarkster

I'm sorry, I don't see what you're doing here.
The more I think on it, a better solution would be use 2 cylinders and a 90 degree torus in a separate body, then cut that body from the first one. It's more complicated, but I think the result is a better model. This would more closely mimic the real world solution of an elbow and 2 sections of pipe. In this video I used additive cylinders and an additive torus, then did the cut. I was going to use subtractive features in order to avoid the extra boolean, but I got a message saying you can't added subtractive features to the empty body, so I decided to go this route instead. The video is a bit longer than I would have liked, but I had to fiddle around getting the placements and rotations like I wanted. I'm not that familiar with this procedure, so it was a learning process for me, too.

phpBB [video]


Edit: Thinking more on it, maybe a more streamlined approach would have been to place the torus first, then pad those faces out.
Edit2: Attached finished FCStd file.
Attachments
RevD-L2.FCStd
(85.2 KiB) Downloaded 4 times
Last edited by TheMarkster on Fri Sep 07, 2018 1:08 am, edited 1 time in total.
My FreeCAD video series on youtube: https://www.youtube.com/playlist?list=P ... GEBlLshYGa
chrisb
Posts: 22532
Joined: Tue Mar 17, 2015 9:14 am

Re: Intersecting pockets

Postby chrisb » Thu Sep 06, 2018 10:38 pm

TheMarkster wrote:
Thu Sep 06, 2018 6:57 pm
I was going to use subtractive features in order to avoid the extra boolean, but I got a message saying you can't added subtractive features to the empty body
You must not use a new body. If you use the existing the idea with subtractive torus works. Some fine tuning may be necessary, I used expressions in most places, but not everywhere.
Attachments
RevD-L_cb.fcstd
(116.21 KiB) Downloaded 6 times
TheMarkster
Posts: 1201
Joined: Thu Apr 05, 2018 1:53 am

Re: Intersecting pockets

Postby TheMarkster » Fri Sep 07, 2018 1:00 am

chrisb wrote:
Thu Sep 06, 2018 10:38 pm
You must not use a new body. If you use the existing the idea with subtractive torus works. Some fine tuning may be necessary, I used expressions in most places, but not everywhere.
Yes, that's much better way than my way, fewer operations and all in the same body.
My FreeCAD video series on youtube: https://www.youtube.com/playlist?list=P ... GEBlLshYGa
chrisb
Posts: 22532
Joined: Tue Mar 17, 2015 9:14 am

Re: Intersecting pockets

Postby chrisb » Fri Sep 07, 2018 1:03 am

There are some residues left inside. I have created a new topic concerning refinement of torus. It turned into refinement of primitives.
Goodwill
Posts: 1
Joined: Fri Aug 31, 2018 8:47 am

Re: Intersecting pockets

Postby Goodwill » Fri Sep 07, 2018 10:43 am

Hi Chris, can you please link to that topic? I can't seem to find it.
chrisb
Posts: 22532
Joined: Tue Mar 17, 2015 9:14 am

Re: Intersecting pockets

Postby chrisb » Fri Sep 07, 2018 9:00 pm

Goodwill wrote:
Fri Sep 07, 2018 10:43 am
Hi Chris, can you please link to that topic? I can't seem to find it.
https://forum.freecadweb.org/viewtopic.php?f=3&t=30755