Why cura messes up with my walls?

[adetogni 0]

Hi, I'm a novice in 3d printers, actually my first 3d printer is going to arrive next week. Meanwhile, I'm learning as much as possible, and playing with Cura in preparation. 
Today I created a first 3d model in tinkercad, with some carved texts. 
I am aware that maybe it is too much detailed for 3d printing BUT I don't understand why Cura decides to make the walls in the TEXT area in  this messy way (going back and forth instead of linear, therefore taking a HUGE amount of time for such a simple model). I am probably doing a very basic mistake.

To make the text I created the SVG file in a differnt tool and imported into TinkerCad and then I did a carve (not sure if it's the right word 🙂 ).
Any help?

 

thanks!

Copy of gatta ci cova (7).stl

[GregValiant 1,141]

Without knowing your settings there is no way to tell what is going on.

With the model loaded and Cura ready to slice with your settings - use the "File | Save Project" command to create a 3mf file.  It will contain the model, your settings, and your printer.  Much better to check than just the STL.  Post the 3mf here.

 

I sliced that STL at .2 layer height and at layer 51 the pupils of the eyes start.  There isn't anything below them so they will fail without support and getting support out from below that delicate structure isn't going to end well.

 

Regarding the time involved...FDM is not a fast process.  You aren't allowed to complain until the prints get over 40 hours.  When you wake up to a pile of spaghetti covering something that for 30 hours had been a perfect print  THEN you get to complain as much as you want.

 

What printer did you decide on?

Edited December 4, 2022 by GregValiant

[adetogni 0]

Hi @GregValiant thanks a lot for the quick response!

I'm attaching the export (even if Cura generates a zip which I'm not allowed to attach here, so I added .3mf, hope it works).

 

I don't understand why the pupils start at level 51, as far as I know, they're drawn in yellow so I understand that's the "top"? Shouldn't cura automatically fill those areas that are too shallow to have support?

 

As I said I'm really new into this (but I am not a novice at all in computer science), so I did take a PDF from this logo, modified it a bit in Tinkercad and generated an STL. There might be a lot of tweaking to be done.

 

But I actually scaled it down to 70mm width (about 50%) and those pupils are printed "fine". However if you look at the letters AND for example at the tip of the ear, I don't understand why it does not follow a single line, but decides to make an up-and-down pattern. Same with the eyes...why it's not printing a circle? Is that a matter of walls size?

 

(I know that FDM is not fast 🙂 , it just that THOSE pattern in the walls looks very weird compared to the other "test slices" that I did - without actually print, of course)

I've bought a Creality Ender 3 S1. Based on a lot of research seemed a very good start...not too basic not too expensive.

gattacicova.3mf

[GregValiant 1,141]

Cura splits up the line types according to your settings.  You have "wall count" set to 2 so if there is space left after printing the Inner and Outer wall then Cura will use the top/bottom pattern to fill the area.  That's the yellow lines you see.  If lines are running in parallel to the inner wall (green) then that is likely the "Extra Skin Wall Count" set to 1.

 

The eyes are different in the 3mf file.  They will print fine.  What will also print fine is the centers of the "a"'s and "o"'s and the "g".  Unfortunately they aren't connected to the main body and will fall apart when you take the print off the bed.  When letters go through a model you have to watch for that.  Better to make the letters like an old style stencil with connectors going to the loose parts.

 

 

These letters get glued onto another print and so they just needed to stay together long enough for me to attach them.

The little bars are pretty flimsy but they get the job done until the super glue takes hold.

 

 

The slice looks normal to me.  Maybe if you post a screenshot marked up with the areas you are questioning it would be clearer to me.  We try to talk apples and apples here but sometimes it doesn't happen.

 

I have an Ender 3 Pro.  It started out on shaky legs but over time we've learned to get along.  When you put your printer together pay close attention and use a carpenter square to make sure that the XYZ axes are as close to perpendicular to each other as you can get them.  Just be cause some parts were assembled at the factory does not insure that they were assembled correctly.

 

[adetogni 0]

Ouch, those floating "a" and "g" are very rookie mistakes, I didn't notice them! Thanks! Unfortunately this is the font they use for the logo, so I'll have probably to find a way around it (either I add a tiny "connector", like a stencil, for those suspended areas, or I just remove them)

What I am saying are these "ragged" lines.

 

It looks like the slicer decides to NOT follow a curve around the letters, but decides to go "back and forth" on those edges. Is this fine?

 

Same for the eyes

is it normal that draws this * instead of a circle, for the pupil?

 

Maybe I'm overzealous...can't wait to arrive (should be around end of this week...or later).

While we're here...I was actually thinking of printing the "base" of a colour and then the cat shape of another, and then glue it, so it will be nicer to the eye...but maybe I'm going too far from now. I'll need to start printing some cubes and little tests before adventuring in these special cases :-))

 

Thanks for the suggestion on the ender setup. I'm quite good in manual tasks and I'll be very precise, I'll check the perpendicularity. This comes with autoleveling, so I'll do a manual leveling first (I've seen some youtube videos) and then autolevel
 

thanks a lot!

[GregValiant 1,141]

That's just the way the lines are rendered on-screen.

Cura has two video modes.  If your computer video system supports OpenGL 4.1 (or higher) you get smooth fancy 3d graphics.  For those of us who don't have OpenGL 4.1 then Cura works in "compatibility mode" and you get the flat 2d representation.

In compatibility mode each extrusion is shown as a rectangle whose dimensions are Line Width by Length of Extrusion.  The rectangles are joined at the line ends (those black lines down the center of each rectangle) but no attempt is made to add a radius or smooth the intersections.  You get one rectangle going this way and the next going off at an angle and you can see the square short end of the rectangle.  In reality the nozzle fills that gap with a radius.

[adetogni 0]

cool, that explains a lot. In fact I'm using a "temporary" old computer for slicing...time to update my gear 🙂

 

It is actually strange since in theory this ubuntu 22 should support OpenGL....I'll check

[ahoeben 1,886]

9 hours ago, adetogni said:

It is actually strange since in theory this ubuntu 22 should support OpenGL....I'll check

It is not just a matter of the software; your hardware (GPU) must support OpenGL 4.1 or newer.

[adetogni 0]

6 hours ago, ahoeben said:

It is not just a matter of the software; your hardware (GPU) must support OpenGL 4.1 or newer.

being this a 10-years old computer it _might_ be the case...:-)

[ahoeben 1,886]

I like your optimism 🙂

[adetogni 0]

2 hours ago, ahoeben said:

I like your optimism 🙂

🤣 anyway, for this reason and several others, I just ordered a new pc with i5, 16GB ram and 512 SSD. That SHOULD make it 🙂

[GregValiant 1,141]

Well...that might leave me as the only one around here still nursing a steam powered video system.  I just can't bear the thought of giving up my Commodore though.

[adetogni 0]

ZX Spectrum FTW!