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13.06.x infill leaves object

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You're asking for a 100% overlapping infill with the wall, that's what you are getting if you account for the fact that the wall is 0.4mm in width. Exactly as designed.

Your SW, your decision, but importing old setups results in a two times larger overlap.

Maybe a note or a warning would be helpful...

 

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Although I had an intuitive sense of how this is working, I did have to stop and think about it a bit... so, I put together some examples, just to clarify the way it's working for myself, and I'm posting them here as they might be useful for others, and because I think there might be a problem with it....

So, 0% overlap is printed so that the centerpoint of the end of the infill line is just touching the inside of the perimeter bead of plastic. For instance:

0% overlap, perpendicular

The yellow dot marks the coordinates of the endpoint of the infill line - i.e., the center of the nozzle opening. Note that in practice, something approaching a semicircular blob of plastic would extend past the yellow dot into the wall.

A 100% overlap means that the centerpoint of the end of the infill line just touches the outside of the adjacent loop:

100% overlap, perpendicular

 

Again the yellow dot shows the centerpoint of the nozzle, so in practice the outer edge of the circle would be sticking through the wall.

 

Where it gets complicated is if the wall and infill don't meet at right angles. In that case, even more of the infill can stick out past the wall:

 

100% overlap, off-angle

 

This is what is happening in the example in the original post - which only shows the center lines of the beads, not their width.

 

Part of me wonders if it's ever valid for any part of the infill to pass completely through the wall? Perhaps the clipping algorithm should consider the width of both beads, (and the end cap on each line?). I wonder whether, given a suitably complicated geometry, it might be possible for even a 15% overlap to protrude through the wall? At the very least, its possible even in simple cases for some slightly suspect things to happen like this:

 

15% overlap in Cura 13.06.5

 

This is a square rotated 46º off axis, and then with 25% infill, - but just the 'recommended' 15% overlap. The net effect is far more than 15% co-incidence of the lines, and I suspect that trying to re-extrude over the single wall that's already there is going to deform the wall.

 

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It seems that what cura is calling 0% and 100% infill should be called 50% and 150% infill. And what the old cura called 15% infill is now called -35% (do negative numbers work?).

 

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It seems that what cura is calling 0% and 100% infill should be called 50% and 150% infill. And what the old cura called 15% infill is now called -35% (do negative numbers work?).

The SF infill routine worked quite different from the current routine, as it also added a partially extra perimeter line as part of the infill. This causes a whole different bonding with the sides then the new infill routine. If you would use -35% on the new infill it would not bond with the side walls at all. (you can actually do this, but it does not make sense)

Once again, I see no issue here, except for comparing 2 vastly different methods. The "diagonal overlap" from illu might be an issue if you have a 0.4mm horizontal shell, but I do not think it will effect the actual print in reality. Extrusion has a way of taking the path of the least resistance.

 

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Daid -

1) Is this overlap percentage also applied to the solid infill on tops and bottoms? (From my tests yesterday, it looked like it probably was, but I wasn't paying that much attention). If it is, then I think that's going to add quite a bit of excess extrusion at the ends of the lines if we keep the old settings? (What if, in my 'diagonal overlap' example above, it was a solid infill layer - there really wouldn't be anywhere for that extra plastic to go?)

2) In the old style infill, where it drew partial extra perimeter lines, I presume that with a zero percent overlap, that extra perimeter line ran just along the inside of the existing perimeter, rather than overlapping it? So on the 'diagonal' infill lines the nozzle centerpoint was stopping half-a-nozzle-width short of the perimeter, to leave room to turn and follow alongside the perimeter?

3) It does seem like in the general case, with the new slicer there's going to be rather more overlap between the infill and wall, for any given percentage infill overlap setting? Not that it's a problem, but it is different.

4) If, previously the 'right' number was 15%, does that mean that now the right number we should recommend is different now? As George mentioned, it does look like -35% would allow the end of the semi circular 'end cap' on the infill line to just stick 15% into the old wall, which perhaps seems closer to the old behavior?

 

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