Support wipe-to-object and wipe-to-infill

[vintagepc]

I had to disable/remove the wipe options to get this working initially. Figure out how to re-implement those; it'll be tricky since you no longer have the purge volumes available to calculate from the tower, and they can be tricky to determine based on the object, owing to Plicer isssue 2855 (prusa3d/PrusaSlicer#2855)

[bynnek]

In the old script on gitlab, you left the purge tower active but moved it off the bed basically correct so you could get these volumes? Was the reason you ditched that method in the new script because it was painful to put a wipe tower out off the bed?

Couldn't the prints technically overlap with the wipe tower in PSlicer and you still extract them from the gcode later? I thought it the tower code is pretty clearly remarked in the gcode at the start and end with the "CP EMPTY GRID" or "CP TOOL CHANGE START (end END)". When you arrange your print bed and put the wipe tower overlapping with your actual parts, it'll try to physically print them both in the same space even though they will interfere.

[vintagepc]

Complexity. I wanted to greatly simplify a lot of the handling, this old code comprised a good chunk of the code and it was not maintainable (at some point between 2.0 and 2.2, it broke and I didn't get very far at locating the issue. I'd rather strip it out and rewrite that path if I have to (there are some other options for volumes - I may just submit a PR to the plicer project for the 2.20 release to get access to the volumes directly). than continually chase bugs in it as the upstream project changes the output format.

[vintagepc]

I've filed a pair of upstream pull requests to expose the needed purge volume as part of the custom toolchange gcode. If those are approved it will mean we can do this without needing to resort back to enabling the WT and stripping it out.

Marking as scheduled, since it will require (hopefully) PS 2.2 for the capability.

[bynnek]

That would be rad! Is there a ticket somewhere I can go chime in on to try to pressure them?

[vintagepc]

Sure, you can watch them here:

prusa3d/PrusaSlicer#3550
prusa3d/PrusaSlicer#3534

and associated PRs:
prusa3d/PrusaSlicer#3573
prusa3d/PrusaSlicer#3576