Pocketing

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RobB
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Posts: 72
Joined: Sun May 26, 2019 4:02 pm
Location: Alpnach, Switzerland

Pocketing

Post by RobB » Tue May 03, 2022 3:53 pm

Attached file has a rectangular object with an internal island. Both are polylines. Most of the times, the polyline offset command does not see the internal polyline and writes the whole block full of parallel lines. I have tried to change the polyline direction, regenerate them etc, but if it properly generate the pocketing area is a hit or miss. What is required for both polylines to keep the inner line as boundary?

Thanks, Rob


Version:
3.27.3.0 (3.27.3)
Internet:
QCAD.org
Build Date:
Apr 28 2022
Revision:
a6c73c5
Qt Version:
5.14.2
Architecture:
x86_64
Compiler:
gcc 5.4.0
150-02 Stepper connector plate for mini ITX box.dxf
(147.22 KiB) Downloaded 273 times
Linux Mint 20 , qcadcam-3.24.3.10-pro-linux-x86_64

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Husky
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Location: USA

Re: Pocketing

Post by Husky » Tue May 03, 2022 6:53 pm

Hi Rob,
RobB wrote:
Tue May 03, 2022 3:53 pm
What is required for both polylines to keep the inner line as boundary?
The Polyline Offset tool is not able to detect the inner polyline by design.
I recommend to use a single offset plus an exploded hatch to pocket that area. Depending on your needs it could look like this ....

Husky-2022.05.03-01.png
Husky-2022.05.03-01.png (17.62 KiB) Viewed 2355 times
BTW: Lunch in this drawing also the "Detect Zero Length Entities" tool to get rid of the "imperfection" ... :lol:
Work smart, not hard: QCad Pro
Win10/64, QcadPro, QcadCam version: Current.
If a thread is considered as "solved" please change the title of the first post to "[solved] Title..."

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andrew
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Re: Pocketing

Post by andrew » Tue May 03, 2022 8:09 pm

To make sure the offset tool recognizes islands, you need to select all the contours and then use the offset tool:
Screenshot 2022-05-03 at 21.08.09.png
Screenshot 2022-05-03 at 21.08.09.png (49.47 KiB) Viewed 2344 times
See also user manual at:
https://qcad.org/doc/qcad/latest/refere ... /OffsetPro

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Husky
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Posts: 4935
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Re: Pocketing

Post by Husky » Tue May 03, 2022 8:21 pm

Ouch .......... my bad! :lol: :lol: :wink:
Work smart, not hard: QCad Pro
Win10/64, QcadPro, QcadCam version: Current.
If a thread is considered as "solved" please change the title of the first post to "[solved] Title..."

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andrew
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Re: Pocketing

Post by andrew » Tue May 03, 2022 8:27 pm

It's easy to miss as it's an unusual use of selections. But it's the only convenient way to "choose" multiple entities for an operation.

RobB
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Posts: 72
Joined: Sun May 26, 2019 4:02 pm
Location: Alpnach, Switzerland

Re: Pocketing

Post by RobB » Tue May 03, 2022 9:10 pm

Thanks,

I got the method from this forum topic:
https://www.qcad.org/rsforum/viewtopic. ... php?t=5411
In trying, I selected probably everything a few times, hence that is why it sometimes worked.

Will try again.

Thanks Andrew.

Edit: Just tried again, and now I see that there are two icons for Offset: Polyline Offset (alternative) in 'Misc Draw' which I used all times, and Polyline Offset in 'Polyline', which worked as desired. No idea what the difference is.
Linux Mint 20 , qcadcam-3.24.3.10-pro-linux-x86_64

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