Multi-material printing request: Retract when crossing interface shells

[jonaskuehling]

The "interface shells" option for multi-material (or -color) printing is great, but would be even better when those interface shells (=internal perimeters..) would also trigger retraction, so that the materials/colors don't get mixed up during non-retracted internal travel moves.

I think one would only activate die interface shells option anyway, when highest color-/material-separation even inside the object is intended. For example with at least one translucent material.

Think about a dual-color print from red and translucent material. There would be lots of red strings (travel without retraction from one red island to the next, potentially crossing translucent regions) inside the translucent volume.

Should be standard I think, simply never cross any kind of perimeter (be it outside or inside/interface) without retraction.

(Again, I think I have already read about this kind of request somewhere, but cannot find it again, unfortunately. Let me know in case there' already some milestone marking for it...)

Talking about 1.1.7-stable btw.

[jonaskuehling]

Basically it's a detail-improvement of #1847 ...

[alranel]

I see what you say.
However, the Interface shells option doesn't generate internal perimeters but only internal solid horizontal shells between materials. Internal perimeters are always generated if adjacent regions are assigned to distinct extruders. I agree with you that it should trigger retraction if a region boundary is crossed.

[alranel]

Done!

[jonaskuehling]

Ah ok, now I got it!

Thanks for fixing the retraction issue in any case, will test that shortly with further "manual soluble support prints" (manually generated support volume to achieve close contact between model and support).

BTW did you make any progress in terms of a "soluble support" option lately? Should be quite easy since support would just needed to be generated with model layer height, instead of dynamically calculated height to end up with the desired space to the object like it's wanted for break-away-support. Further the object's supported regions mustn't be printed like bridges but just like any other full-contact-layer, squished perfectly on top of the support interface.

You know we'd pay for it, don't you? ;) Would be just one chance to give at least something back for your awesome development so far.