FR: Allow adjustment of Seam Staggering distance

[psiberfunk]

Is there an existing issue for this feature request?

• I have searched the existing issues

Is your feature request related to a problem?

Yes. During my exhaustive quest to optimize scarf seams, I realized that staggered inner seams can help, but not as much as i'd like them to be able to. The root cause of this is that using inner seams that are aligned, or closely aligned, with the start of the scarf, causes deformations on the outer walls of the scarf. This is particularly true because the start of an inner scarf seam starts with a detraction with the nozzle at the same layer height as the old layer... leaving a "landing mark".

This "landing mark" squish makes this particularly problematic when using the otherwise useful "inner scarfs" option that helps improve final object surface quality. It looks like this picture below on the first inside wall, and you can clearly see how this affects the outer wall. As the outer wall is MOST vulnerable to issues near the scarf overlap zone (typically 20 mm long by default), and this is where this mark is landing, this is very likely causing issues with the overhang performance:

Which printers will be beneficial to this feature?

All

Describe the solution you'd like

I would like to be able to adjust the stagger distance for the inner seams.. particularly so that the nearest inner wall seam start (the one closest to the outer wall) can be offset to either before or after the "scarf zone" ( which is 20 mm by default).

Ideally when "staggered seams" is turned off, there would be an "offset" parameter in mm that would attempt to offset the value of the inner seam by XX mm. A good default value might be -10 or +10 mm for a scarf seam (I will happily run experiments!). This would offset the first inner wall seam by a fixed amount, and then all subsequent inner wall seams would be computed as they currently are based on that fixed offset.

I believe that the code lives in SeamPlacer.cpp around here somewhere

Describe alternatives you've considered

I have tried almost everything under the sun to optimize this away. I have run hundreds of experiments to optimize the seams in the challenging overhang scenario, and the best settings are currently listed here. However, I do not believe I can further optimize the overhang performance without being able to adjust the inside seam offset.

Additional context

As described here already, poorly staggered inner-seams that are closely aligned have issues with even traditional walls. Scarf seams, because of their delicate nature at low extrusions , are particularly sensitive to inner wall effects on outer walls where the scarf is , even when using inner-outer-inner wall order to try and minimize this.

Ideally we would be able to stagger the seams "away from the outer scarf" by using an adjustable offset for the start of the staggering (e.g. the nearest inner wall would be offset by X mm).

[Hammerfest]

Thanks for the breakdown, i thought I was doing something wrong

[CCS86]

I agree, this would be a great feature.