Arcs from exploded ellipse are not smooth

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mwarce
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Posts: 1
Joined: Sat Feb 19, 2022 12:32 pm

Arcs from exploded ellipse are not smooth

Post by mwarce » Sat Feb 19, 2022 12:52 pm

Hi!
I am going to purchase QCAD Pro so I can explode splines and ellipses to arcs. I tested the trial version (downloaded today) and arcs exploded from splines are smooth. A line from the end point of one arc to its centre passes through the centre of the next arc.
However, when I exploded an elliptical arc that was not the case. There was a 1.5 degree difference in the ending and starting angles. Is this by design or is it a bug?
As the function is still timesaving, I am going to buy the licences anyway (I need two). However, every time I will have to delete alternate arcs and fillet so that I get a smooth curve. I just wanted to mention that it seems wrong as it is.
Thanks,
Miguel

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andrew
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Posts: 9036
Joined: Fri Mar 30, 2007 6:07 am

Re: Arcs from exploded ellipse are not smooth

Post by andrew » Sat Feb 19, 2022 3:06 pm

mwarce wrote:
Sat Feb 19, 2022 12:52 pm
However, when I exploded an elliptical arc that was not the case. There was a 1.5 degree difference in the ending and starting angles. Is this by design or is it a bug?
Not a bug. This type of smoothness is only guaranteed when exploding splines.

You could offset the ellipse by a small amount (e.g. 0.1) and then offset if back by the same amount. The first offset will give you a spline (as an offset ellipse it not an ellipse), the second offset will give you a polyline that should be reasonably smooth.

Modify > Offset (with Distance)

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