Question about retracts

[Johncoffee]

I have a question that just puzzles me while printing out a iPhone case:
During the printout the print head nozzles relocates a couple of times to start printing again. So far so good. I observed that there was some oozing and found out that there was no retract of the filament done. Even worse, the print head didn't lift up for 0.3mm while moving and just sort of scratched over the surface. This made resulted in some noise during movement over the printed 'lines'.
When looking at the nozzle movement code in Mattercontrol, I can clearly recognise that there was no retract and that the head stayed at the same layer hight while moving that far.
Question: Is this a fault of the slicer engine (Matterslice) or is this just fact?

Here a picture of what happened and this green line also showed on the actual print out as a scratch. (I've marked it with a green arrow)

Why wasn't there a retract?

Thanks for clarifying!

*John*

[Johncoffee]

some other 'scratch movement' - see below

[Polygonhell]

I don't use matter-slice, but most modern slicers won't retract on moves inside of infill, unless the move is greater than some threshold, in addition there is usually a minimum move length after a retract before another one can be performed.
Usually Z-Lift is coupled to retraction, so if it doesn't retract, there is no lift.
KisSlicer has controls that expose both of these thresholds, I have no idea if matter slicer has equivalents.

[Captain Starfish]

I got the latest alpha of MatterControl the other day and have noticed the opposite - it's doing retracts on infill before following the infill around (ie not crossing perimeter) until it reaches the next place.

There are some settings now dealing with retracts between islands and things like that, might be worth having a play and see how they turn out in the preview.

If you're still at a loss, send your stl and saved settings together with software version number and a description of the issue to [email protected] - they're pretty good at getting back to people and it may turn into a new version with better retract control for me, too!

[Johncoffee]

Thank you both for your answers. I'll get in touch with matter control's support once to get their response on this!