kicad-developers team mailing list archive

[Cirilo Bernardo <cirilo.bernardo@xxxxxxxxx>]

3D MCAD will generally represent even simple circular arcs as B-Splines,
so it it likely that your arcs were written to DXF as B-Splines or Bezier
curves.
Use librecad to draw the arcs instead; 2D CADs will generally represent
conics as a Euclidean formulation on a Cartesian plane. Re-exporting will
not fix the issue because it would be very unusual for a 2D CAD to analyze
a B-Spline and convert it to a Euclidean conic.

I can see a use for polynomial splines and B-splines as graphical objects
in KiCad (including the board outline) but this requires some thought on
how we represent such objects without having a negative impact on the
code or file format. Such a feature would allow greater freedom in the
design
of the board outline (a useful feature for some commercial work) and would
also allow us to represent odd items from other ECADs such as the elliptical
arcs of Altium and gEda. While representing an actual ellipse using the
typical Euclidian formulation on a Cartesian plane is a nightmare, a
B-Spline representation is actually fairly easy to manipulate. Of course a
graphical editor for polynomial and rational B-splines would be a challenge
to develop, but it's been done before.

- Cirilo


On Wed, Sep 9, 2015 at 2:54 PM, Marcos Chaparro <nitrousnrg@xxxxxxxxx>
wrote:

> Seems that is kind of Berzier Curve, not few arcs. Probably that shape
>>> needs to
>>>
>> split to single arcs before import.
>
>
>
> Um, I don't know if its converted to a bezier curve, but I'm sure I made
> it from 4 arcs, see attached.
>
>
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