Bug or my bad model design?

[maker2]

In the following model of a cylinder there is a Y shaped branch that is entirely symmetrical with a width of 2mm (the same as the wall of the cylinder). I cannot persuade Simply to put infill in one of the branches. This is not a catastrophe but I'm keen to understand what is going on.

Any suggestions?

(nozzle width 0.35, extrusion width 0.42, infill 50%, gap fill where necessary 10%)

[dkightley]

Try upping the number of outline/perimeter shells up to 3. That will give you a solid wall for the main tube and webs, rather than it trying (badly) to fit 50% infill in the narrow gap.

Note that the infill in your screen shot is coloured orange....and when you make the change, the infill that the slicer puts in will be gap infill...coloured light green.

[jimc]

if dougs way doesnt work then you can also try going the other way with it and do 1 single perimeter allowing much more room to add infill. on thin walled or detailed prints, especially text... i always try and run single perimeter.

[maker2]

Thanks.

Both approaches work well and I'll try single-wall infill for fast prototyping, triple wall gapfill for serviceable product.

Given the symmetry of the Y-shape I'll conclude that the problem is not space but that the slicer somehow becomes confused in there.

It also looks like its algorithm concludes "if I can't print BOTH of an inside perimeter pair, then I won't print either". It could instead reason "there's just room for one perimeter wall and so I'll squeeze it in". Then we could have 3 perimeter walls, which I've heard some people (and printer manuals) recommending for certain situations.

[dkightley]

Given the symmetry of the Y-shape I'll conclude that the problem is not space but that the slicer somehow becomes confused in there.

Given the symmetry of the Y-shape I'll conclude that the problem is not space but that the slicer somehow becomes confused in there.

It also looks like its algorithm concludes "if I can't print BOTH of an inside perimeter pair, then I won't print either". It could instead reason "there's just room for one perimeter wall and so I'll squeeze it in". Then we could have 3 perimeter walls, which I've heard some people (and printer manuals) recommending for certain situations.

To expand on what I said in my first reply, the slicer is applying the in-fil pattern (in this case, a hexagonal design) onto a tee shaped area.....and there's bound to be a proportion of the area where nothing is put. In your case, on one out of three bits of the tee section. Its not a deficiency or bug in the software, its just the end result of it doing what its been set up to do.