Ok - i’ve screwed up three glass engravings trying to do it without the crumb tray, and using math. Each time the engrave has been substantially high and to the left, and about ⅔ the size it shows on the screen.
Another user has created a “no-math focus ruler” that I plan to try next. (No-Math Focus Ruler)
So here’s my stupid (probably) developer question: - Wouldn’t it be relatively simple for the developers to put in a toggle in the interface for with/without crumb tray, and then just measure the depth of the item you want to engrave? If it’s over/under the allowable focus, that should be an easy warning trigger.
Just bring the engraving surface into the correct range, and then use Set Focus on it.
The engraving surface needs to fall between 1.4" to 1.9" from the bottom of the machine. The Glowforge can’t focus below 1.4"…make sure the engraving surface (top) is above 1.4".
Thanks for the answer @Jules, that’s right. I’m going to close this thread - if the problem reoccurs, go ahead and post a new topic. Thanks for letting us know about this!