Issue: Lightburn would not burn curves from an SVG file to the test article. I tested multiple files, broke down the objects in the file to individual curves (burn selection), grouped/ungrouped/regrouped, did what I could to simplify the content. Under all tests, none of the curves would burn. Even creating a simple circle primitive or curve (line tool) inside LB and asking it to burn that was a fail. Polygons worked w/o issue the whole time.
I dug into machine settings and started individually toggling the various options. The fix was to change the transfer method from synchronous to buffered. Once I made that change, et voila!, things worked as expected.
The question I have now is: Why? Why would changing transfer mode from sync>buffer enable curves to burn? Don’t get me wrong, I’m super happy it’s working as expected. I do, however, like to understand.
laser: Creality 5w
LB: latest/greatest
A “curve” consists of a gazillion tiny straight lines. Attempting to follow a curve at high speed produces some multiple of a gazillion bytes of G-Code.
When the USB link can’t keep up with the ensuing command stream, odd things happen.
Buffered mode improves USB throughput by using the character buffer available in the laser controller, rather than handshaking each command one-by-one.
For your controller, that’s evidently enough to maintain the pace. 
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Thank you for that explanation!
I learned something today. I guess it’s time to go home now.
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