Fix Spiral Z-Hop arc handling #1560

New Issue

MrUnknownDE · 2026-04-05T18:23:49+02:00

MrUnknownDE commented

2026-04-05 18:23:49 +02:00

Originally created by @kisslorand on 11/21/2025

The existing issue

Spiral Z-Hop was still generating arc moves (G2/G3) even when arc fitting was disabled in Orca.
This meant the G-code did not follow the user’s settings and could cause issues on printers that are not using arc mode.

Why this was a problem

When a printer or firmware has arc support disabled or not fully implemented, unexpected G2/G3 commands may cause:

the move to be ignored entirely
the move to be executed as a straight line instead of an arc
small unintended XY shifts or jitters
desynchronization between the internal planner and the actual toolhead position
random “micro bumps” on retraction or travel moves
firmware warnings, errors, or “unknown command” messages

These behaviors depend on the firmware, but all stem from the same root cause: arcs were emitted despite the user disabling them.

What this PR changes

Spiral Z-Hop now checks the arc fitting flag properly
If arcs are disabled, the spiral lift is approximated using linear segments
If arcs are enabled, the expected G2/G3 arc is used

Result

The G-code now respects the user’s configuration
No more unintended arc commands in non-arc mode
Predictable and consistent Spiral Z-Hop behavior across all printers, regardless of their arc support level

Screenshots

Arc fitting disabled, spiral ZHop selected

Before:

After:

*Originally created by @kisslorand on 11/21/2025* --- #### The existing issue Spiral Z-Hop was still generating arc moves (G2/G3) even when arc fitting was disabled in Orca. This meant the G-code did not follow the user’s settings and could cause issues on printers that are not using arc mode. --- #### Why this was a problem When a printer or firmware has arc support disabled or not fully implemented, unexpected G2/G3 commands may cause: - the move to be ignored entirely - the move to be executed as a straight line instead of an arc - small unintended XY shifts or jitters - desynchronization between the internal planner and the actual toolhead position - random “micro bumps” on retraction or travel moves - firmware warnings, errors, or “unknown command” messages These behaviors depend on the firmware, but all stem from the same root cause: arcs were emitted despite the user disabling them. --- #### What this PR changes - Spiral Z-Hop now checks the arc fitting flag properly - If arcs are disabled, the spiral lift is approximated using linear segments - If arcs are enabled, the expected G2/G3 arc is used --- #### Result - The G-code now respects the user’s configuration - No more unintended arc commands in non-arc mode - Predictable and consistent Spiral Z-Hop behavior across all printers, regardless of their arc support level --- ### Screenshots Arc fitting disabled, spiral ZHop selected __Before:__ ![Before](https://github.com/user-attachments/assets/c3d0ec30-c8b8-4f8e-844f-4bf8e59460dc) __After:__ ![After](https://github.com/user-attachments/assets/6a43000f-aa1f-429f-bf5f-21dfc79b2668)

MrUnknownDE closed this issue

2026-04-05 18:23:49 +02:00

Sign in to join this conversation.

No Label Community testers wanted Community testers wanted Community testers wanted Community testers wanted Community testers wanted Community testers wanted Community testers wanted Community testers wanted Community testers wanted Community testers wanted Community testers wanted Community testers wanted Community testers wanted Community testers wanted Community testers wanted Community testers wanted Community testers wanted Community testers wanted Community testers wanted

1 Participants

Notifications

Due Date

No due date set.

Dependencies

No dependencies set.

Reference: github/OrcaSlicer#1560