[BUG] Lift Height jumps to Retract Height in Pocket Clearing toolpath

[batcrave]

As shown in the attached file, at a certain setting of Linking->Lift Height the actual calculated lift height stops following the specified value and instead jumps straight to the Retract Height.

With a 0.125" tool, a .26866" Lift Height value will behave as expected, but a 0.26867" value will always lift all the way to whatever Retract Height is set for.  With a 0.2" tool, it jumps at 0.488754", so there's clearly a relation to tool diameter, although it's less clear what that relation is.

In the example file I've set Retract to 2" to make the change more visible. The example toolpaths are also showing "Lift Height exceeds the maximum stepdown" warnings because I borrowed the settings from the model I was working on when I stumbled across this, but it appears to happens independent of the stepdown setting and/or its relationship to the lift height or tool size.

I haven't tested any other toolpaths (this just happens to be what I was using when I discovered it), so I don't know whether it's isolated to Pocket Clearing.

This isn't anything I particularly need fixed - it's easy enough to work around in my case - but I was desperate for a distraction from wor but it was unexpected enough behavior that it seemed worth reporting (and, unlike the #$%&!!% vanishing stock bug that keeps cropping up, it was easy to reliably repro).

-Bats

(...but if we had an in-client bug report option, it would've been easier to report *hint*hint*)

[seth.madore · Accepted solution]

Bats,

I like your strikeout text 🙂

While I do see the weirdness, I don't think this is something that's going to get a lot of attention. Why? Because the purpose of that "Lift Height" field is intended to be in the range of a few thou or so, not several times the diameter of the tool. The Lift Height is intended to prevent the tool from dragging across the floor when your "Max Stay Down" is large enough to prevent a full retract. If you were to say, crank the "Max Staydown" to a low value (sub .100") and returned Lift Height to a more reasonable value, you would find that the tool would pocket out at one depth, rapid up to the Retract Height and then Rapid back down and cut the next level

I will send a note along to the Tooltip folks and see if they can add some clarity of intent to the tooltip

File is attached if you'd like to see what I did

[batcrave]

No worries - like I said, it wasn't anything that was causing me any particular trouble - just something that looked like it was unlikely to be intended behavior, and, being simple to repro, looked like a great way to avoid doing whatever it was I was supposed to be doing.

And, yeah, I was well aware that I was horribly abusing the Lift Height when I ran into it, but somehow it seemed like I wasn't getting the effect I was looking for from Max Staydown (I can't say why, though, since now it seems to be doing exactly what it's supposed to - unless I just got confused about what I did/didn't have set after one of those increasingly frequent vanishing-stock-induced crashes).

Either way, as long as the report has made it to the people who such things need to be reported to, I'm content to let them worry about whether it's worth worrying about.

(Now, an in-client non-fatal bug reporting mechanism, on the other hand, that's still something I'd like to see worked on - it would make life so much easier if I didn't have to come all the way here to the forums to distract myself like this)

-Bats

( there's a slim chance it might even increase my productivity... slightly... maybe. )