A request

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debenriver
Posts: 523
Joined: Sat Dec 03, 2011 9:19 pm
Location: Maine USA and Suffolk England
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A request

Post by debenriver » Sun Nov 15, 2020 10:23 pm

Hi Eric

I am increasingly having to produce DXF files of drawings of components for CNC cutting.

The parts that I draw are often quite complex shapes, consisting of polygons with hundreds of sides – like this:
Screenshot 2020-11-15 at 17.05.31.png
Screenshot 2020-11-15 at 17.05.31.png (87.66 KiB) Viewed 82 times
CNC cutting can't cope with discontinuous path lines (gaps, crossovers, doubles etc). After I have drawn the component, I use ⌘J to join all the lines – sometimes takes several attempts, specially where a sharp corner has been cut with a radius fillet. Once all the lines join OK I turn the shape into a polygon using ⌥⌘P. Then I check using Action >> Length, area, center. If the polygon has an area (S=12345), then I know that at least there are no crossed lines. But if there is a gap, or if the sides of the polygon go past each other like this:
Screenshot 2020-11-15 at 16.51.06.png
Screenshot 2020-11-15 at 16.51.06.png (95.02 KiB) Viewed 82 times
I get an area OK but don't always see that it's not a truly closed polygon. And when it comes to CNC cutting the component, the G-code will fail it.

My question:

Is it possible to provide an option (only an option - not a default) whereby I can select for, say, Action >> Length, area, center only to produce an area if the polygon is truly closed? Or produce an alert – "Polygon is not closed" – something like that?

I know it's a special case – but preparing drawings for CNC is becoming increasingly necessary (for me anyway)

Keep well and keep safe – increasingly difficult in this country at the moment ...

Cheers -- Goerge

Eric Pousse
Posts: 742
Joined: Sat Dec 03, 2011 12:31 pm
Location: Tours - France

Re: A request

Post by Eric Pousse » Mon Nov 16, 2020 5:55 pm

Bonjour George,

Try "Length, area, center" with RealCADD 5.02b3 with option key down...

Thanks.
Eric Pousse

debenriver
Posts: 523
Joined: Sat Dec 03, 2011 9:19 pm
Location: Maine USA and Suffolk England
Contact:

Re: A request

Post by debenriver » Mon Nov 16, 2020 10:05 pm

Absolutely Perfect. :mrgreen:

Thank you very much indeed.

Still got a problem with my beamcamber script – see other post.

And the drawings seems much darker and bolder with b3 than with b2 – is that deliberate??

Cheers -- George

Eric Pousse
Posts: 742
Joined: Sat Dec 03, 2011 12:31 pm
Location: Tours - France

Re: A request

Post by Eric Pousse » Tue Nov 17, 2020 7:40 am

A polygon is marked as closed if delta x and delta y between the first and the last point are <= 0.00001.
Eric Pousse

Eric Pousse
Posts: 742
Joined: Sat Dec 03, 2011 12:31 pm
Location: Tours - France

Re: A request

Post by Eric Pousse » Tue Nov 17, 2020 9:02 am

debenriver wrote:
Mon Nov 16, 2020 10:05 pm
And the drawings seems much darker and bolder with b3 than with b2 – is that deliberate??
Yes George, I made some modifications to test the speed but I don't know if it is definitely or not...
Eric Pousse

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