Polylines and Circles

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BrianB
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Polylines and Circles

Post by BrianB » Wed Oct 28, 2015 2:49 pm

Hello I am relatively new to cad in general so forgive the noob aspect of this question :) I have a drawing that someone created in inventor and it has circles that are made up of a lot of equal length polylines. I know that they are polylines because Qcad says so. Is there a way to convert these polylines into a singular circle in Qcad? I am asking this because when I import the file into my cam program I have to join the polylines to make a complete circle and I would like to join them in Qcad instead.

QCAD 3.10.0.0

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andrew
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Re: Polylines and Circles

Post by andrew » Wed Oct 28, 2015 3:01 pm

The easiest way I can think of is to use the tool Draw > Circle > 3 Points and then click three points (not too close to each other) on the polyline.

There is no automated way, I'm afraid.

BrianB
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Re: Polylines and Circles

Post by BrianB » Wed Oct 28, 2015 10:27 pm

Alright. Thank you for the reply. Could this possibly be a feature request?

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andrew
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Re: Polylines and Circles

Post by andrew » Thu Oct 29, 2015 1:11 pm

Could you attach your file? I probably misunderstood what you meant. I'm not sure if the circles are represented as polylines with tiny line segments or for example polylines with two arc segments or something like that.

BrianB
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Re: Polylines and Circles

Post by BrianB » Thu Oct 29, 2015 7:47 pm

Here is the file attached. The problem is any of the circles in the drawing are not true circles or at least not like if I used the circle tool in QCAD.
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Bottom .078.dwg
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Husky
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Re: Polylines and Circles

Post by Husky » Thu Oct 29, 2015 8:42 pm

I face many times drawings like this one coming from unknown sources. It's always challenging to prepare something like this for a proper cnc task.

Andrew has already mention the best way to go - 3 Point circles and 3 point arcs. After tracing a given "Line circle" with a 3 point tool I check the Property editor to see the diameter / radius result and change it manually to the next reasonable value. Mostly easy to do in metric - not so easy to do in imperial.

I would really appreciate to get some kind of "automatic tool" - but I see also the problematic ...
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Clive
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Re: Polylines and Circles

Post by Clive » Wed Nov 04, 2015 12:50 pm

BrianB wrote: I have a drawing that someone created in inventor and it has circles that are made up of a lot of equal length polylines. QCAD 3.10.0.0
If you are going to get any more drafts from Inventor, simply ask if center point references can be placed instead, then you can draw the circles in QCAD yourself, oh and make sure you charge for the clean up :)

BrianB
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Re: Polylines and Circles

Post by BrianB » Fri Nov 06, 2015 2:49 pm

Sorry for the long wait to reply. Thank you for the steps and suggestions.

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