CURA 2.4 Infill

[ultiarjan 1,221]

I just noticed the difference between infill settings of the Ultimaker3 and Ultimaker2.

At 20% infill you get a 3.5mm line distance on the UM2, but a 5mm line distance on the UM3.

At 100% infill you get a 0.35 mm line distance on the UM2, but a 1 mm line distance on the UM3.

So it looks like on the UM3 you don't get the amount of infill you asked for I guess roughly calculating that a 5mm line width is less than 20% .... so it looks like the UM3 settings are wrong.

All with 0.4 nozzle, 0.2 layer, 0.35 line width

[ghostkeeper 105]

There is more to the line distance: It gets multiplied if there are more directions of lines on one layer. For instance, triangle infill has 3 directions of lines (making it triangles). This makes the infill thrice as much in theory (practice is a little different). Because it extrudes three times as much, the distance between the lines must be greater to achieve the same infill percentage. Grid has only 2 directions for the lines. This also illustrates the difference between the UM2 and the UM3 since they have different defaults for the infill pattern.

For the more technically inclined, the precise formula that's being used to compute the line distance is this:

 

0 if infill_sparse_density == 0 else (infill_line_width * 100) / infill_sparse_density * (2 if infill_pattern == 'grid' else (3 if infill_pattern == 'triangles' or infill_pattern == 'cubic' or infill_pattern == 'cubicsubdiv' else (4 if infill_pattern == 'tetrahedral' else 1)))

 

The only place where the infill density is significantly incorrect is cubic subdivision, because which cubes are subdivided is only known after slicing. There isn't a real good solution to that at the moment but that is technically a bug.

In practice there are of course other differences, because the material gets blocked by other materials when it moves over a previously placed infill line in a different direction. Also above 100% infill it starts to waver, of course, because the material gets blocked.

[ultiarjan 1,221]

This also illustrates the difference between the UM2 and the UM3 since they have different defaults for the infill pattern.

 

I understand what you're saying, but I do think there is an error in the UM3 settings, my comparison was in both cases with "GRID". The UM3 gets significantly less infill with the same settings, and 100% fill is not solid but 1 mm line width...