Doesnt Calculate Thin Walls

[Achuta]

Hi there,


first of all , i love Kisslicer.

so far the fastest slicer with the best support.


i only have 1 problem. i have a few thinwalled objects now to print, but kisslicer refuses to calculate these walls 0.5 mm .

it starts the slicing but calculates these walls with 0 extrusion.

Any1 know what causes this problem ??


Greetings

Achuta

[ba0547]

Hello,

i also have this problem, generated a small box to calibrate/measure my flowrate. kisslicer prints something, but not all. some items of my box (blends) are missing at all.

haven't found a solution for that problem in kisslicer, other slicers are printing my box correctly.

best regards, harald.

[PenskeGuy]

Walls thinner than 2X Extrusion Width are not considered to be full walls. If you have an open-topped box with .5mm modeled walls and .5mm Extrusion Width specified, there cannot be a complete path around the object. A complete path in this case would be two Extrusion Widths wide; one around the outside and a return around the inside (which to KS is STILL outside... because it is) to where the layer began. Computations that may show a one Extrusion Width path are really Crowning paths and are not recommended for anything requiring integrity or accuracy; they are only low resolution fill paths to take up space where a complete path won't fit. If your "other slicer" works the way you want, use it.

[plexus]

thanks for the explanation of that detail. very important and I didnt know this either. so do you mean if I am using an x mm nozzle, I can't print a wall x mm wide, ie. the extrusion width only?

[Dreide]

Unfortunately, KISSlicer's calculations are not really consistent regarding thin walls (or in general, perimeters and loops touching themselves at the inside). The attached STL has a wall thickness of 0.6mm and is sliced well with up to 0.5mm extrusion width (oversample resolution 0.04mm) - it comes out thicker though as two 0.5 wide extrusions side by side don't add up to 0.6, obviously. If sliced with 0.52 extrusion width, KISSlicer even adds a crowning path in between, so something is not quite right with the calculations.

[PenskeGuy]

thanks for the explanation of that detail. very important and I didnt know this either. so do you mean if I am using an x mm nozzle, I can't print a wall x mm wide, ie. the extrusion width only?

You can. It uses a different approach, however. To use a simple example, a solid box with Infill = 0, Skin Thickness = 0, Loop = 1, will print a one Extrusion Width wall.

What you have to understand is that KS looks at the object as having an Inside and an Outside. A solid box has its Outside on the 6 faces and Inside between the 6 faces. That which you can see is the Outside, that which you cannot see is the Inside.

A modeled wall box having no top or bottom has its Outside on BOTH sides and top and bottom of the modeled wall. IOW, you can see the outward-facing, upward-facing, downward-facing and inward facing-faces. That is the Outside; because you can see them. Its Inside is the inside of the wall itself. IOW, you can't see it. Two objects cannot occupy the same space at the same time. This is why it will not compute a complete path around the Outside; because there isn't enough space.

It is possible to have Crowning print the 1 Extrusion Width wall but it isn't reliable and requires a really accurate model. Any variation in modeled wall thickness will truncate the path if it drops below a threshold value. That, and Crowning is only meant to do quick infills of voids where a complete path does not cover. They are always inside the part, so don't matter much if they are, for lack of a better term, sloppy. Therefore, it isn't very accurate itself.

[PenskeGuy]

Unfortunately, KISSlicer's calculations are not really consistent regarding thin walls (or in general, perimeters and loops touching themselves at the inside). The attached STL has a wall thickness of 0.6mm and is sliced well with up to 0.5mm extrusion width (oversample resolution 0.04mm) - it comes out thicker though as two 0.5 wide extrusions side by side don't add up to 0.6, obviously. If sliced with 0.52 extrusion width, KISSlicer even adds a crowning path in between, so something is not quite right with the calculations.

Took a look at your file. You'll notice that the paths are complete up to a Z of 2.250mm and then above that the corners don't form continuous paths. Due to the non-uniformity of the wall thickness, they break apart into two or three sections at each corner and are inconsistent in the breakage as Z increases, due to the way the model is constructed. When upping the Extrusion Width to 0.52mm, Crowning takes over when the wall becomes too thin to accommodate a complete path all the way around the Outside using the increased Extrusion Width. Even then, the model's wall thickness varies enough that the Crowning disappears completely in many places; leaving entire sides missing. That was with v 1.2.0.1.

1.5 b1.16 acts much the same as 1.5 b2.20, inserting Crowning on top of a path that already fills the space, supplying Crowning only in some places and in others, where the modeled wall falls below the threshold, nothing at all.

[Dreide]

You'll notice that the paths are complete up to a Z of 2.250mm and then above that the corners don't form continuous paths. Due to the non-uniformity of the wall thickness, they break apart into two or three sections at each corner and are inconsistent in the breakage as Z increases, due to the way the model is constructed.

I did not observe this. With 0.5 extrusion width, the perimeter is closed, with 0.52, an additional crowning path is placed in between and, for most layers (above Z=3mm), goes all around. On layers where it doesn't, crowning has one gap at each corner. Okay, with 0.52, I actually found a layer where also the perimeter broke. This is with v1.5-Beta-2.20-Win64 and with oversampling resolution 0.04mm (and crowning threshold 4mm). Oversampling resolution is crucial here. With 0.05mm it looks more like what you described.
Normally I can manage to get thin walls printed sufficiently well, but it is always a matter of trial and error until I get all the relevant parameters (or the model) adjusted. It would already help to know how KISSlicer decides whether it can get two loops squeezed in and when crowning paths are placed. I understand the basic idea of how perimeters need to form closed loops and when crowning paths are placed and how model resolution can affect both, it is just that sometimes KISSlicer's calculations are way off.

[plexus]

This issue is the same as I was having and posted about in the beta thread. frankly this makes no sense. why would a slicer allow a model to slice in a way that is not printable? with KISS now, you have to manipulate a bunch of parameters that appear to have no documentation on how they work together in order to try and get a printable slice. when I ran into this problem, I noticed that reducing the nozzle size (extrusion width) was the only way to get the model to print. I had never experienced this before with KISS.

I am sorry but if KISS now requires some 5 or 6 parameters that interact with each other to be precisely set in order to get a useful print, well, its gone outside the boundaries of what is usable.

Should I be moving on to Slic3r or something? how is all this a feature with a benefit? it seems like a liability for KISS.

I am no slicing god like Pensky et al. I just want to set parameters that reflect the physical print and slice and rely on getting a file that will just print. I don't really want to have to learn how all these parameters interact to try and try and try to get a file that will print.

Or... what I am missing here? I thought it was supposed to be Keep It Simple Stupid?

Update: yep, slic3r just... works. also tried a file that a client sent over that prompted my post in the beta thread: Slic3r also slices it fine with a 0.5mm nozzle selected. KISS will not slice this model in a printable manner unless I change the nozzle diameter.

The problem for me is that I do work for clients and I can't be spending a bunch of time trying to get KISS to give me a printable file. also requiring me to change out nozzles to print is also not something I am keen on as it consumes time that I generally not getting paid for. I am going to have to use Slic3r in cases where KISS fails.

There must be something I am missing here... it can't be possible that KISS simply doesn't work for certain models. if someone can tell me/us what we need to set so that we can rely on KISS to work, or tell me/us that yes in fact it's true and that we should consider another slicer because KISS just doesn't work for certain models...

[Davide Ardizzoia]

"why would a slicer allow a model to slice in a way that is not printable? "
I can understand your frustration.
But I've hit several times the above problem with all slicers (Cura, Slic3r, Simplify,...) especially when support structure was complex...and KS was the only one to get the job done.

WIll try to make next manual release a bit more clear...hopefully (BUT I AM NOT up to the level of Penske or other black belts around here...)

As Dreide already pointed out: oversampling is your friend, and that's one of the reasons for KS speed. Set it low enough and it will slow down to crawl like other slower slicers..

Best Regards
Davide Ardizzoia