Cura slicing removes details -- perversely

[lairdb 3]

I got some weird results slicing engraved lettering, and the more I fiddle with it, the weirder it gets.

To test the issue, I made a plank with lettering engraved at heights (up from the baseplate) from 0.1 to 1.0mm:

Cura brings in the STL fine (the 0.1 is hard to see but present, the 0.2 and deeper are clearly present.)

If I slice at 0.25 layer height and inspect layer 1, it does no path at all for 0.1 and 0.2, and layer 1 gets 0.3 and deeper.  This makes reasonable sense.

What makes no sense at all to me is that if I reduce the layer height at all, I actually lose detail.  Here, I reduce the layer height to 0.06 and view layer 1.  What I would expect was to get at least the 0.2 lettering, and maybe the 0.1.  Instead, the 0.3 also disappears!

WTF?

(I've posted the STL here, if anybody wants to duplicate; I've duplicated on two different PCs, and I've tried varying bottom thickness, fill, and nozzle without making any difference.)

[danilius 118]

Tried to download the STl file, but had no luck.

[swordriff 119]

Me too! I would like to have a go at it!

Edited May 10, 2015 by Guest

[nallath 1,124]

The file is not published yet. You need to make it public first.

[Labern 775]

Its dependent on your Initial layer thickness. for .25layer height you will need to set the initial to 0.2 to get all details and for 0.06layer you will need to set the initial layer height to 0.1

not sure why, but that's how you get around it.

[lairdb 3]

Er, sorry about un-published STL. Just Published it.

[lairdb 3]

Its dependent on your Initial layer thickness. for .25layer height you will need to set the initial to 0.2 to get all details and for 0.06layer you will need to set the initial layer height to 0.1

not sure why, but that's how you get around it.

That's... somewhat counterintuitive.

[gr5 2,269]

 

@labern - could you explain this more? Something strange here. Or maybe @daid could explain. I thought if initial layer height was .1 then it would slice the first/bottom layer as a slice through the STL .1mm from the bottom. Regardless of layer height.

[xisle 34]

I think your .stl may be the issue. Was it made in Tinkercad?

Try this .stl with 0.1 to 1.0 mm cut-outs generated at 1 micron. Cura still has some odd behavior IMO, but getting the 0.1 mm cut-out to slice is no problem where I was unable to with your .stl.

[Labern 775]

I find I have the same problem with yours @xisle and don't think it's caused by the STL i have used stl's from various programs that do this.

I can't really explain why cura is doing this but I have had various issues with this while scaling models down to print and just found this to be the issue.

Sometimes it even chops the bottom layer off entirely but then adds another layer onto the height. example set the layer height to 0.25 and the initial to 0.1

[xisle 34]

@labern, that is the odd behavior I was referring to, but seems to occur when layer height is >=2 times the initial layer height, which is not a common setup IME. I also get an unexpected first slice difference between 0.1 and 0.2 for layer height with 0.2 initial layer for both.

With the OP's .stl I found no way to get the "0.1" to slice, even with 0.01 mm layers... OK, I just tried 1 micron (for all layers) and there is something there but it isn't a clean cut-out like the others and is only 0.004 mm deep at most.

[Labern 775]

 

@xisle, Yes you are correct, I just downloaded his file and tried it. I does seem to have an issue with the "0.1"

[lairdb 3]

@xisle, Yes you are correct, I just downloaded his file and tried it. I does seem to have an issue with the "0.1"

(Aaargh -- retyping this whole post because forum doesn't cope well with multiple tabs.)

Yes, some sort of issue. Even though it looks good in Tinkercad (1.1mm letter height, 0.1 sunk into surface):

...it doesn't read cleanly in Cura. In fact, I can get this if I set silly layer heights:

[lairdb 3]

Having said that, in the still-weird category:

I updated the model to include top and bottom lettering (added to the same YouMagine link) and in that STL, the 0.1 renders well (if I adjust the layer and first layer to see it at all):

However, if I go back to my original first layer of 0.3, I still get the slicing perversity where 0.06 layer height yields less detail than 0.25:

[Labern 775]

However, if I go back to my original first layer of 0.3, I still get the slicing perversity where 0.06 layer height yields less detail than 0.25:

Yes you will, even if your STL is good. that's where you need to adjust the initial layer. Maybe this wont be a problem in PU