When slicing an object in vase mode with bottom layers set to 0, extrusion is started before the extruder is at the object's starting point. If the object is is the first to be printed after the purge line, a line of extrusion is laid down between the purge line and the object. The correct behavior is for extrusion to stop during the move from the purge line to the object.
If more than one object is being printed and the object with 0 bottom layers isn't the first, the behavior is even weirder. In this case, extrusion starts above the correct starting point, at the same level as the height of the previously printed object. In the sliced preview, this looks like a line of extrusion leading from mid-air down to the object. The correct behavior is for the extrusion to start only when the extruder reaches the proper starting point for the object being printed.
Project file & How to reproduce
Steps to reproduce: just slice the project and it will match the included screenshot.
Description of the bug
When slicing an object in vase mode with bottom layers set to 0, extrusion is started before the extruder is at the object's starting point. If the object is is the first to be printed after the purge line, a line of extrusion is laid down between the purge line and the object. The correct behavior is for extrusion to stop during the move from the purge line to the object.
If more than one object is being printed and the object with 0 bottom layers isn't the first, the behavior is even weirder. In this case, extrusion starts above the correct starting point, at the same level as the height of the previously printed object. In the sliced preview, this looks like a line of extrusion leading from mid-air down to the object. The correct behavior is for the extrusion to start only when the extruder reaches the proper starting point for the object being printed.
Project file & How to reproduce
Steps to reproduce: just slice the project and it will match the included screenshot.
vase mode bug Prusa Slicer 2.7.4.zip
Screenshot of the erroneously-sliced file
Screenshot of the code leading to the third object (the one with the spiral above it)
Checklist of files included above
Version of PrusaSlicer
2.7.4
Operating system
Windows 11
Printer model
Prusa MK3S+ with Revo hot end