[solved] Offset path is incomplete

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yetanotheruser
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Joined: Sat Dec 30, 2017 2:49 pm

[solved] Offset path is incomplete

Post by yetanotheruser » Sun Dec 31, 2017 4:03 pm

Hi all,

I am using the Modify - Offset (with Distance) function to outset this polygon by 10 mm:
Image
However, the result is not as expected - note the gap in the lower right corner:
Image

Can anyone tell me, what causes this gap? To my best knowledge the original polygon consists of one continuous line - when hovering over it, one can see, that the complete polygon is selected. Therefore I don't understand what causes this strange result. For me it looks like the original polygon is somehow discontinuous, but I can't see how this should be the case.

The dfx file (with only the original polygon) is attached.
Operating system: Windows 10 x64
QCAD version: Qcad Pro 3.19.2

Thanks for any hint on this!
Attachments
back.dxf
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Last edited by yetanotheruser on Tue Jan 02, 2018 2:24 pm, edited 1 time in total.

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Husky
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Re: Offset path is incomplete

Post by Husky » Sun Dec 31, 2017 8:49 pm

Did you uncheck "Clipping" in the option bar?
Husky-2017.12.31-03.png
Husky-2017.12.31-03.png (20.86 KiB) Viewed 804 times
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yetanotheruser
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Posts: 27
Joined: Sat Dec 30, 2017 2:49 pm

Re: Offset path is incomplete

Post by yetanotheruser » Mon Jan 01, 2018 4:32 pm

Thanks, that was it - after unchecking this option everything worked as expected :D
Can you tell me when this option is useful and when not? What's the intention behind this function?

The clipping option is actually not mentioned in the Offset documentation ):
https://qcad.org/doc/qcad/latest/refere ... ro_en.html

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andrew
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Re: Offset path is incomplete

Post by andrew » Tue Jan 02, 2018 1:24 pm

Gaps are usually caused by tolerance issues. These tend to occur if a polyline contains arc segments with very large radii as is here the case.

A potential solution (other than turning off clipping) might be to straighten all arc segments into line segments using Draw > Polyline > Arc to Line Segments.

yetanotheruser
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Posts: 27
Joined: Sat Dec 30, 2017 2:49 pm

Re: Offset path is incomplete

Post by yetanotheruser » Tue Jan 02, 2018 2:23 pm

andrew wrote:Gaps are usually caused by tolerance issues. These tend to occur if a polyline contains arc segments with very large radii as is here the case.

A potential solution (other than turning off clipping) might be to straighten all arc segments into line segments using Draw > Polyline > Arc to Line Segments.
Thanks for the explanation and alternative workaround :D

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