Above: Polyline test file used and the result(s).
>> General consensus from yesterday: DXF > CAM
If you don't care about best or being best friends with the CAM bods
and/or the artwork is simple and needs no modification, then polylines are fine.
If you want to try and use polylines and the artwork has curves with lines
then use a high precision poly-line output or accept 'squared off curves'
Moi polylines or all polylines typically 'work' on all cam systems,
but test and preview 1st.
If you use ACAD then "save as" dxf format R12 is a quick legacy trick to turn
arcs or curves into lots of lines. "POLY-LINES".
>> Moi native dxf polylines export allows enough control over precision
use higher/highest precision for curves. ANGLE 1-5 passed my quick evaluations.
Michaels R12 export template can also be considered.
SPLINES:
Splines dxf export from moi or all drawing packages
can also work depends on the cam software. This is a bit
'you might get lucky' as Chris indicated.
If you save out dxf OLDER than R12 from a drawing package or acad
the geometry, precision or 'angle approximation' seems to always be bad.
NEWER than r12 and its usually splines thats unless we presume your
software let's you draw lines as lines and curves/arcs as arcs (not beziers, splines etc).
** Saving in r12 seems to 'explode'' all splines to polylines BUT
then a simple '2d circle' created in any software might become 750+ polylines.
Other commands can be used in autocad to get the desired polyline result
PEDIT, FLATTEN, JOIN, for example. You can also check precision. There is maybe some
Lisp functions out there that might convert both lines and splines to lines+arcs
but I'm not using autocad nor interested to go back to it (once used as a file converter).
Other uses for R12/polylines:
Some ECAD software still has really limited dxf importers
so R12 'polylines' is great for them.
WATERJET & GLASS CNC NOTES:
> All polyline files can work 'fine' but if the cam operator needs
to use offsets or increase or change anything then polylines are simply
a lot of work.
> On flow waterjet and "workstation 1" with FLOWPATH software spline dxfs could be imported
but sometimes not without issues making them unworkable...sometimes the shapes was totally messed
up or "auto path" function that explodes the splines and then joins them together for a 'cut path' showed
how it struggles with the spline entities [see slot image].
> On INTERMAC glass cnc systems it seemed to cope with dxf spline artwork
straight out of drawing packages - I used export as dxf ACAD 2000 from Coreldraw.
MOI Spline based dxf export would likely work as well. Eitherway, these splines are seemingly
always exploded and then joined in the cam software; for the toolpath.
When converting from splines worked in the cam import process then that circle in my test file might have been
about 150+ lines vs 750+ lines from 'hi res' polyline only.
When I used a polyline + arc dxf format the circle was just 4 arcs
and the design could be tweaked a lot easier by the cam operator if
needed.
Polylines (only lines) might be seen as reliable but not ideal
and likewise splines are a bit hit and miss; all depended on the cam
software version for each machine.
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UPDATE:
For a seemingly easy conversion splines>arcs, this is one option:
https://www.cadkas.com/dxf-splines-to-arcs.php
I since have contacted these people and if interested any Moi3D
users can purchase the tool here with ~10% discount.
https://order.shareit.com/cart/add?vendorid=200026514&PRODUCT[300992879]=1
Disclaimer: I am not affiliated nor have I tested this software yet,
I do not earn commissions.
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ACAD users can also do a load of mouse clicks and commands
like FLATTEN, REGEN etc, and try this:
https://www.youtube.com/watch?v=XGR1FeRNjx4
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