Cura 2.3.0: How to print only two perimiters?

[Gnevko 5]

Hi, people!

I try to play a heard. It should have only two perimiters, top and bottom layers. But if I define Infill density as 0% ...

 

Cura places some strange additional volumes (yellow lines) ... How is it possible to avoid such behavior?

Edited September 20, 2016 by Guest

[dwardio 4]

Since you have 0% infill, you might try checking your model's wall thickness and make sure it is a multiple of your nozzle diameter. Default nozzle is 0.4mm, so best results for a 2-wall model would be approximately 0.8mm. If this doesn't match up, you can get some really odd results.

[ultiarjan 1,223]

Actually since cura 2.xx the idea is that the wall quality is better with lines just a bit less than nozzle size. Therfore the default wall lines are set to 0.875 times the nozzle size (if I remember correctly).

[Gnevko 5]

S3D works in this case correctly .... hm ...

[bagel-orb 61]

Those yellow lines are top/bottom fill. If you don't want that, you should set the Top Layer Count and Bottom Layer Count to zero.

You could get it fixed using Infill Meshes, but those are probably a bit too advanced to get this working with easily.

[Gnevko 5]

Thank you for the answering. Top/bottom fill ... hm ... it's just a middle part of the object (on my first screenshot) it should be at least 2 or 3 cm till the Top.

[ahoeben 1,968]

Say you have a sphere. Does a sphere have a top layer? What is the top of a perfect sphere? Is it a singular point, or the entire top half of the sphere?

Because the top half of the sphere gradually gets smaller, each layer of the top half is a top layer in a way.

For something like a cube, the difference between walls and top/bottom is much clearer.

[Gnevko 5]

Say you have a pyramid. Does a pyramid have a top layer?

Or the walls with the same tilt angle on each layer and a singular point on the top? The walls of a sphere have  just different tilt angles on the each layer ...

Edited September 10, 2016 by Guest

[ahoeben 1,968]

Let me try to explain it in a different way. Cura tries to make sure that where-ever on your model you drill straight down you pass at least the top thickness amount of material. If you have sides at a tilt-angle, Cura needs to add material to enforce that "rule".

Yes, your pyramid has layers that are regarded partially as top layers. That was exactly my point.

[Gnevko 5]

Thank you for the explanation! My be it will be possible to add some configuration to avoid this rule? To set top layer to 0 - it is not gut idea, in this case I have just a hole on the top of my model ))) (but the walls in this case have really only two perimeters)