Strange behavior of pocket MOP for some fancy text

[jasonharper]

I'm getting some very strange behavior in CamBam 1.0, trying to use a Pocket MOP to laser engrave some text (originally in SVG, converted to DXF with inkscape).  I've done exactly this process many times before, I have no idea why it's misbehaving this time...

A simple .CB example of the problem is attached, with just two letters.  Both happen to consist of one outer outline, and one inner island - I get the same behavior if I leave them all as polylines, or convert them to regions.

If I use a Region Fill Style of Horizontal Hatch (the one I actually want), Vertical Hatch, or Inside Offsets, the "O" works, but the "H" is blank - no toolpaths generated for it at all.


If I use Outside Offsets, the MOP actually works - but this produces visibly inferior results to Horizontal Hatch on my laser, so isn't usable.


And if I use Inside + Outside Offsets, I get this mess - note that the "H" is avoiding its island by a huge margin for no apparent reason, while the "O" is actually cutting into its island.


Any idea what's going wrong here?

[dh42]

Hello

Maybe some treatment can solve your problems ; the polylines contains very small arc segments (Pic 1), an "arc fit" (tolerance = 0.001) seems to solve the problem with the H (Pic 2)

For the differences between the top and the bottom with Outside Offset, it is because the shape is not identical, at the bottom it is the polyline that is opened to forme the space between the legs but on the top it is another shape used to do this .. so different results

https://cambamcnc.com/forum/index.php?topic=1624.0

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David

[dh42]

Re

I don't know if this can be useful, but another way is to fill the shape with a pattern, then use an engrave operation to cut the pattern.

You can use the following plugin to generate patterns.

http://www.atelier-des-fougeres.fr/Cambam/Aide/Plugins/Hatch_EN.html

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David

[jasonharper]

Arc Fit 0.001 fixed all of the other problem letters, as well.  Thanks for your help.

[stevehuckss396]

In my experience when I get unpredictable behavior it's usually a problem with the dxf file. Open poly or some kind of irregularity. Check the lines in the problem letters to be sure.