Disabling Z-Hop leads to wrong nozzle height

[Kulfuerst]

I found that disabling Z-Hop either globally or in the material setting overrides (setting Z-Hop to 0) leads to the wrong nozzle height on the first layer, if the object is preceded by a prime tower. Weighing both the faulty and intact prints of a single layer shows identical weight of both, clearly indicating that this is NOT an underextrusion problem. Measuring the test body height reveals a first layer height of 0.6 mm instead of the required 0.25. The issue is fully repeatable across both nozzles and materials and can be toggled reliably with the z-hop setting. The G-Code of defective and intact prints appears to be identical, suggesting that the issue originates somewhere in the accessory files of the g-code.3mf file and firmware interpretation.

Bambu Studio Version 2.4.0.70
Printer: H2D
FW Version: 01.02.02.00

[mugglesmuggle]

When you say the g-code appears to be identical, it can’t be, one of them must include z-hop and the other not, did you diff them or just look at them?

[Kulfuerst]

They can be identical. If you inspect the g-code.3mf that the slicer sends to the printer you will see that there are in fact many additional files contained in there besides the actual g-code. A misplaced or misinterpreted 0 in one of these files may well lead to some internal turmoil of the FW as it executes the g-code.

I did indeed diff them. And believe me, I was just as confused at first.