How does PS handle thin layers?
I'm mostly just curious as a test model I created tapers (linearly) from about 1mm to about 0.05mm on the build plate. I expected PS to chop off some of it as it was much thinner than my printed layer height. I was hoping to learn how much would be chopped off. It did chop off some of the model, however I'm wondering how the algorithm determines how much to chop off because it chops it off at exactly the same place whether I slice at 0.15mm layer ht or 0.30mm! I really expected more to be chopped off proportional to the layer height. Can anyone explain why the part is chopped off the same for both layer heights? Near as I can tell, the height of the model at the point of being chopped off would be about 0.1mm.
Additionally, I sliced at 0.05mm for kicks.
Best Answer by Ringarn67:
@sherri
First layer is 0,2mm, regardless of layer height, that's why.
If you lower, or raise, your first layer it will be different.
But, you can't go lower than 0,2 on MK3, it is a safety thing.
Actually you can, with some trickery
I misunderstood you in the first place, I thought of a wall that tapered upwards, from 1 to 0,05mm
RE: How does PS handle thin layers?
@sherri
It depends on perimeter width, at the height the wall becomes too thin printer can't print it.
And that height is the same regardless of layer height.
Look att perimeters in slicer you see what I mean.
Also, slice the same model with different printers, 0.25, 0,4. 0.6 etc nozzle and compare
Prusa i3 MK3S+ FW 3.11.0 (kit dec -20), PrusaSlicer 2.6.1+win64, Fusion 360, Windows 10
RE: Slicer_test project attached.
I don't think this has anything to do with perimeter width in this situation. It's simply a matter of how the slicer determines how far along a slope to print. Does all filament fit under the slope? Or, does it try to average it out like aliased pixels with some layers going over and some going under the theoretical slope.
STL file:
I guess we can't upload PS projects? Here's the STL
Can't upload
Okay... I can't seem to upload any files. 🙁
Zip
@sherri
You need to zip the files.
Prusa i3 MK3S+ FW 3.11.0 (kit dec -20), PrusaSlicer 2.6.1+win64, Fusion 360, Windows 10
Attached files must be zipped
Okay... I can't seem to upload any files. 🙁
It's a "forum thing". All attachments need to be in zip format.
and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan
And a zipped up project 3mf file is preferred over an stl as that has settings etc stored with it which is much more useful.
@sherri
First layer is 0,2mm, regardless of layer height, that's why.
If you lower, or raise, your first layer it will be different.
But, you can't go lower than 0,2 on MK3, it is a safety thing.
Actually you can, with some trickery
I misunderstood you in the first place, I thought of a wall that tapered upwards, from 1 to 0,05mm
Prusa i3 MK3S+ FW 3.11.0 (kit dec -20), PrusaSlicer 2.6.1+win64, Fusion 360, Windows 10
Well that attachment worked. Slicing it with 0.15 as your project has it gives 'stair steps' of a certain size. Slicing it with 0.07 height gives smaller stair steps as it can slice it into thinner layers. Remember the first layer is set to 0.2 anyway by default no matter the layer height profile if using prusa defaults.
As to how much it chops off the top, well thats a case of math. Your model is 1.27mm high. Take off the first layer to give 1.07. Divide that by 0.15 gives you 7 layers with a tiny bit extra which it cant print which is why its 1.25 high after slicing. Do the same with a 0.3mm layer height and you have less layers (hence the greater stair stepping/less steps) but the bit it cant print is the same so same model height. Remember 0.15 and 0.3 are divisible. You get different results if you use 0.1 or 0.07 layer heights
If you use the variable layer height tool it will slice to 1.28 from my quick test which is close.
Solved
@Ringarn67 Great, thanks! That clears it up 🙂
and @Neophyl I appreciate your input. Take a look at the model. It's a ring. When sliced, the tapered edges are being clipped. That's what I was referring to. Being clipped in the xz plane, not the xy. Sorry I didn't make that clear 🙂
My Bad
@sherri
I was corrected via PM
You CAN go lower on first layer, just change "First layer height" to 0,1mm. (or 0,05)
However, when I printed the attached file a minute ago my display says "0,15" on first, second and third layer. On fourth layer display shows 0,2.....
BTW, my first layer looked like crap when I printed it 😀 , probably I need to clean my sheet and adjust Live-Z
Prusa i3 MK3S+ FW 3.11.0 (kit dec -20), PrusaSlicer 2.6.1+win64, Fusion 360, Windows 10