What Determines What Gets Filled/Etched?

Had a quick question. I am etching this on glass for a table with a diamond drag bit. I have done this succesfully in the past on black granite, see picture below. All I did then was select-all and choose pocket and everything seemed to turn out to where it made sense once it was engraved. I used Inkscape on this project. On this next project (Nomad Etch) a buddy of mine used Adobe Illustrator. This one (the nomad etch) is different for some reason though. Why would some of these letters get filled and others not? Is there a way to fix this within CC? What determines how the software knows what to fill and what not to fill when you choose pocket?

I am using a Mac with CC build 449 (2020-01-07). This is a going away project for a Command Sergeant Major who is leaving the unit, the glass will go on top of a whiskey barrel. This is just one design of 7, each representing a Troop, that will be etched into the table top.

Thanks again from Fort Hood, TX.!

the algorithm is more or less the odd/even rule

start on the very left and go rightwards

if you crossed an odd number of lines … it gets filled

even nr of lines, stays open

this normally goes great but gets messy if you have intersecting shapes
best approach is to break the shapes up to not intersect


also some of your picture seems to have double lines close to each other so that it almost looks like one.
the odd even rule still applies even if it looks like one line until you zoom in a lot


another funky thing, some software might put 2 of the exact same shapes smack on top of each other… that’ll STILL count as two lines. but will be hard to see until you try to move one



That seems to have done the trick, it looks like I can manipulate what is etched by removing some of the lines. Thanks for the info!