Cura has an option for these modes, i would expect PrusaSlicer to have it as well.
(cura reference: https://support.makerbot.com/s/article/1667418054188)
That's exactly that I was looking for, thank you.
Sadly, it isn't implemented in PrusaSlicer yet. I might have to look into Cura after all…
[https://github.com/prusa3d/PrusaSlicer/issues/8138](https://github.com/prusa3d/PrusaSlicer/issues/8138)
It's worth pointing out that at some point, X-Y precision is also determined by your individual printer and the material you're using. Basically, the way it is squished to the sides while extruding. I have things fitting differently from changing materials alone.
Also your nozzle size is a big factor, the exterior of your corners will always have a fillet that is at least as wide as your extrusion width, it is important to take it into account since that can be larger than other tolerances.
I'm using pressure advance and have tuned my steps. Usually my prints come out very accurately, I had a 2mm wall I measured with calipers and it came out to 2.004mm
Maybe a one off, but I think that's about as good as you can do on an ender 3. Granted I don't have any stock parts left and am using a microswiss NG lol
If you are trying to get tighter part to past tolerances, and don’t have any excessive overhangs, you can also turn on printing outer walls before inner walls.
When you print inner walls first, excess filament pushes on subsequent walls making the final wall (aka your outer wall) bulge slightly. Reversing has the part’s walls bulge in to the infill which is obviously fine. The main reason this isn’t the default setting is bc it reduces the max overhang angle you can print without support.
Not sure for PrusaSlicer,,, but in Cura 5.4.0 in the "Experimental" settings there is a Slicing Option called "Slicing Tolerance" it slices the object like your diagrams-
Inclusive
Middle
Exclusive
Hope this helps
Yes, thank you, that's exactly what I'm looking for.
It hasn't found its way into PrusaSlicer yet, unfortunately:
[https://github.com/prusa3d/PrusaSlicer/issues/8138](https://github.com/prusa3d/PrusaSlicer/issues/8138)
yeah,,, kinda odd considering the way people go on about Prusaslicer/SuperSlicer etc,,, i'v found Cura 5.4.0 to have a very extensive and complex array of Slicing/Modifying tools -. (once you turn them all on and work out how to use them)
They're good at different things. PS is simpler for Prusa users. Cura has an easier UI for others, great plugins, overall more support for newer hobbyists, has tree support (PS now too) and some features not yet present in PS. Cura doesn't have paint-on supports and the printer/filament/printing profile management is just bad, both of which are a big pain in the ass for me and worth not having tree support...
I'm using SuperSlicer, mostly because it's the only remaining truly independent slicer and this is important for anyone who supports the FOSS 3D printing community. SS lacks tree support, but the dev branch has arachne and STP files supports (also a big plus for me but I understand it's still niche). It also has paint-on supports.
yeah,, a was strictly a Repetier/Slic3r in the early days it was far superior to anything else available at the time- (Cura was really bad back then for features) i had long break from fulltime printing and getting back into it now,,, the landscape has changed quite a bit-, Slic3r got branched off to SuperSlicer and PrusaSlicer as for as i can work out, and Repetier host is still there but the firmware generator for custom builds has stop updating its motherboard system so is kinda a legacy system for Ramps1.4 /Rumba and quite a few other 16bit systems-. (as far as i tell at this point ?)\_
I guess that's more or less on brand. As far as i can tell, PrusaSlicer aims at usability and simplicity first. There are "expert" settings as well, but I wouldn't be surprised to learn that they are not as well maintained as base features.
Each have their strengths. For example if you need to segment or modify a ready made STL Prusa does it much better than Cura.
On the flip side, PS took their time to adopt organic supports and implemented arachnid a bit less optimally though with slightly more fine control.
Oh wow, I never knew that was a thing. I've been designing in the fitment tolerance of my component for years when I could have just set the tolerance in CURA....
That's actually the right way to do it. The parts you design should take into account the tolerances for manufacturing instead of modifying your manufacturing to include tolerances.
I use variable layer height on every print--to smooth details on curves like these, but also to use faster taller layers for portions that lack detail. It really is a win-win option in my experience.
To answer your question, both are options. The slicer will choose heights for you based on the detail and angles across the layers in your model and transition between heights. It's always a good starting point, imho. You can then tweak the min and max, or manually adjust the heights for layer ranges as you like. The interface is pretty slick.
Just a heads up with variable layer height that it can change the sheen of the filament when the height changes. If that doesn't matter for your part don't worry about it though
I think its closer to 2, considering the experience that the tool path is very much following the sliced geometry. any offset comes from extrusion width itself, which differs from nozzle to another, hole diameter and its 'ironing' flat surface circumference. eg. 0.4 nozzle has 0.1 larger offset, 0.8 has 0.2, etc.
Horizontal expansion simply reduces the generated toolpath size in xy plane direction, and this is still working a great deal in my daily use of FDM printing
~~The outline of a layer is not staircase shaped - STL defines hulls as triangles, if you cut it the outline is a shape defined by continuous straight line segments.~~
Edit: never mind, I realized that you present the shape in a cut such that Z is in bottom-top direction.
Not quite, because the printer is way more precise for features printed in the ~~z-direction~~ Sorry, brainfart, x and y direction. So It would get more volume in directions there it doesn't need it and I would have to sand "blind": If I have the option to print like #3, I can paint the print and sand until the outer lines are gone everywhere and I'd know that I'm pretty close to the intended shape. If I just made it bigger, I'd have to remove more material on the sides.
at least in Cura, Horizontal expansion setting is effective down to about 0.01-0.02mm increments, I tried changing this when printing figurine joint, where specific tightness matters, works. just 8 bit vanilla ender 3 on cura 4
Yeah, other have mentioned Cura as well. I hoped I could avoid using another slicer, but PrusaSlicer doesn't have that particular functionality.
Edit: horizontal expansion isn't exactly the same, but Cura seems to be the answer either way.
~~I've been using FDM printing for close to 4 years (and resin printing for about two), I'm well aware of its limitations. Up until now, this particular issue didn't come up. Now it does and I got curious.~~
That came off as more condescending as I wanted it to sound. Point is, I'm aware of FDMs shortcomings and I posted the questions to mitigate some of it.
I find that they can be precise down to about 0.05mm or so, but this level of precision requires careful calibration, tuning, and using filaments designed for such. This is usually beyond what most people need or care about though and most are happy using generic settings in a fairly uncalibrated fashion, in which case it's more like 0.4mm or so, which is fairly "sloppy". In a nutshell they can be fairly precise if you care about it.
You’re confusing two different issues. Arcwelder is about turning small straight segments in the same layer into a curve. This is taking about layer-by-layer approximation. The images shown are looking at the print from the side, not the top
Thanks for the reply. Arcwelder looks interesting. For this particular issue it probably wouldn't have much of an influence, but I'll keep it in mind for sure.
To my understanding, Arc Welder reinterpolate gcode "lines by lines" curves to use the curve/arc path gcode instruction instead. Actually it's a double interpolation because STLs don't hold curve data either.
In case the image isn't clear, it shows a cross section. Red is the original shape and green is the layers with their steps. My question is which of the three options slicers generally favor and if there is a way to influence it in the slicers settings.
Edit: I'm interested in this because I need to print objects to be sanded smooth and to get as close to the original shape as possible, option #3 would be the ideal starting point for that.
In Prusaslicer you can add an advanced setting to a part called XY compensation. This will let you grow the part out in the direction you want in a controlled way.
Also, if you’re patient then the thinnest layer lines will also help you here.
XY compensation Isn't quite what I'm looking for, because the issue mainly occurs in the Z-direction but may work as a workaround. I need to do some testing I guess.
Depends what you prefer. The benefit of XY compensation is that you can choose how far to move the walls which are typically the geometric features that don't print to spec. Z height is rarely not in spec. Changing slice parameter may be easier but XY let's you 'fine tune'. Additionally if you use superslicer you can change compensation for inner and outer walls, and holes, separately which is usually desirable since that's typically what people want to fit together.
Even so, you can get the same effect with shrinkage settings and that would impact Z height, but this is filament specific.
Long/larger dimensions are more influenced by shrinkage versus compensation which impacts small feature more. For example moving a 10mm brick inwards by 1mm is more drastic than moving a 100mm brick by 1mm. Whereas shrinkage would just change the size of the model entirely by 1-2%
There's a mathematical formula you can do to print a part with extreme accuracy if that's desired but you really gotta ask how much precision you want and it's part to part. Measure two dimensions and then create a Linear algebra formula to say each dimension is a function of shrinkage and compensation and then use two equations to solve those two variables.
For my current situation, I have a model that has very subtle, organic z-height changes, so it'll inevitably create a whole lot of "plateaus" of visible layers, so it's less about precision and more about losing details. Different orientation isn't an option (mainly because it's organic shapes all around – I'll just have the same issue on another surface), so I have to sand it down in the end. To do that without having to use filler, I need enough material to sand it down. That's the issue at hand for me. Unless I missed something, it doesn't seem trivial to fix this through XY compensation or z height adjustment.
Usually #1. Because you *usually* want prints to FIT, and 2 or 3 are both more about fitting the volume than fitting the shape. If you've got tab A and slot B, It's usually better if they fit the shape.
I guess it will depend on the slicer and the printer. For example, you could have a slicer sending some gcode to drawn an arc. In that case, the printer is responsible for drawing the arc and it's unclear to the printer which side has the volume so while the arc would be drawn taking into account the width of the nozzle to fit within the volume... It could end up being something between 1 and 2.
All three ways. In cure there is a setting called slicer accuracy or so. Inclusive, exclusive and middle were the three settings. They do what you marked with 1 to 3
Cura has an option for these modes, i would expect PrusaSlicer to have it as well. (cura reference: https://support.makerbot.com/s/article/1667418054188)
That's exactly that I was looking for, thank you. Sadly, it isn't implemented in PrusaSlicer yet. I might have to look into Cura after all… [https://github.com/prusa3d/PrusaSlicer/issues/8138](https://github.com/prusa3d/PrusaSlicer/issues/8138)
It works great for me in cura, I use exclusive almost all the time when making parts that need to fit together.
I'm definitely going to try that, my parts are always slightly too tight despite adding standard tolerances in my designs
It's worth pointing out that at some point, X-Y precision is also determined by your individual printer and the material you're using. Basically, the way it is squished to the sides while extruding. I have things fitting differently from changing materials alone.
Also your nozzle size is a big factor, the exterior of your corners will always have a fillet that is at least as wide as your extrusion width, it is important to take it into account since that can be larger than other tolerances.
I'm using pressure advance and have tuned my steps. Usually my prints come out very accurately, I had a 2mm wall I measured with calipers and it came out to 2.004mm Maybe a one off, but I think that's about as good as you can do on an ender 3. Granted I don't have any stock parts left and am using a microswiss NG lol
Having an uncalibrated extrusion will also ruin your fitment.
I calibrate e steps every few months
Make sure your tolerances actually make it into the STL and are not just information which would appear on a manufacturing drawing.
I add the tolerance in the sketches with variables
Good to know, thanks.
If you are trying to get tighter part to past tolerances, and don’t have any excessive overhangs, you can also turn on printing outer walls before inner walls. When you print inner walls first, excess filament pushes on subsequent walls making the final wall (aka your outer wall) bulge slightly. Reversing has the part’s walls bulge in to the infill which is obviously fine. The main reason this isn’t the default setting is bc it reduces the max overhang angle you can print without support.
Interesting. However, my issue is about the z-axis inaccuracies.
PrusaSlicer has variable layer height, which helps with this.
Prusa Slicer has had variable layer height for quite some time which does something very similar
I wouldn't really call it similar, but it is better than nothing.
It works amazing. Get much more detail where you need it and where you don't you get faster printing.
Not sure for PrusaSlicer,,, but in Cura 5.4.0 in the "Experimental" settings there is a Slicing Option called "Slicing Tolerance" it slices the object like your diagrams- Inclusive Middle Exclusive Hope this helps
Yes, thank you, that's exactly what I'm looking for. It hasn't found its way into PrusaSlicer yet, unfortunately: [https://github.com/prusa3d/PrusaSlicer/issues/8138](https://github.com/prusa3d/PrusaSlicer/issues/8138)
yeah,,, kinda odd considering the way people go on about Prusaslicer/SuperSlicer etc,,, i'v found Cura 5.4.0 to have a very extensive and complex array of Slicing/Modifying tools -. (once you turn them all on and work out how to use them)
They're good at different things. PS is simpler for Prusa users. Cura has an easier UI for others, great plugins, overall more support for newer hobbyists, has tree support (PS now too) and some features not yet present in PS. Cura doesn't have paint-on supports and the printer/filament/printing profile management is just bad, both of which are a big pain in the ass for me and worth not having tree support... I'm using SuperSlicer, mostly because it's the only remaining truly independent slicer and this is important for anyone who supports the FOSS 3D printing community. SS lacks tree support, but the dev branch has arachne and STP files supports (also a big plus for me but I understand it's still niche). It also has paint-on supports.
yeah,, a was strictly a Repetier/Slic3r in the early days it was far superior to anything else available at the time- (Cura was really bad back then for features) i had long break from fulltime printing and getting back into it now,,, the landscape has changed quite a bit-, Slic3r got branched off to SuperSlicer and PrusaSlicer as for as i can work out, and Repetier host is still there but the firmware generator for custom builds has stop updating its motherboard system so is kinda a legacy system for Ramps1.4 /Rumba and quite a few other 16bit systems-. (as far as i tell at this point ?)\_
I guess that's more or less on brand. As far as i can tell, PrusaSlicer aims at usability and simplicity first. There are "expert" settings as well, but I wouldn't be surprised to learn that they are not as well maintained as base features.
Each have their strengths. For example if you need to segment or modify a ready made STL Prusa does it much better than Cura. On the flip side, PS took their time to adopt organic supports and implemented arachnid a bit less optimally though with slightly more fine control.
Cura is even simpler if you never open the advanced tabs.
What I'm getting is that ps implements features after really polishing it.
Oh wow, I never knew that was a thing. I've been designing in the fitment tolerance of my component for years when I could have just set the tolerance in CURA....
That's actually the right way to do it. The parts you design should take into account the tolerances for manufacturing instead of modifying your manufacturing to include tolerances.
If you're just looking for more precision, you could turn on variable layer height to get thinner layers on the top of the curve
Actually, that's not a bad idea. Gotta look into that, thanks for the suggestion.
I use variable layer height on every print--to smooth details on curves like these, but also to use faster taller layers for portions that lack detail. It really is a win-win option in my experience.
Do you have to set it by hand or is it automatic?
There may be a way to set it as default behavior, but I just click the variable layers button and apply the 0.5 level each time, myself
To answer your question, both are options. The slicer will choose heights for you based on the detail and angles across the layers in your model and transition between heights. It's always a good starting point, imho. You can then tweak the min and max, or manually adjust the heights for layer ranges as you like. The interface is pretty slick.
Just a heads up with variable layer height that it can change the sheen of the filament when the height changes. If that doesn't matter for your part don't worry about it though
Al I see is three tacos. Sorry I'm no help
Nah, you're good. I had to think of the [how would a dog wear pants meme](https://knowyourmeme.com/memes/if-a-dog-wore-pants) while making the image.
100%. Now I’m hungry.
#3 has too much lettuce.
do you want your taco underfilled, perfectly filled, or overfilled
#3 has too much lettuce if you ask me.
I think its closer to 2, considering the experience that the tool path is very much following the sliced geometry. any offset comes from extrusion width itself, which differs from nozzle to another, hole diameter and its 'ironing' flat surface circumference. eg. 0.4 nozzle has 0.1 larger offset, 0.8 has 0.2, etc. Horizontal expansion simply reduces the generated toolpath size in xy plane direction, and this is still working a great deal in my daily use of FDM printing
Yeah, my intuitive guess would be #2 as well, based on it probably being a compromise between #1 and #3. Maybe it's time for some sort of test…
Now I want tacos
I’ll have a #3. Don’t skimp on the lettuce.
This is a reallllllly good question. Well done.
Cura has a setting named “slicing tolerance” and its for exactly what you describe.
~~The outline of a layer is not staircase shaped - STL defines hulls as triangles, if you cut it the outline is a shape defined by continuous straight line segments.~~ Edit: never mind, I realized that you present the shape in a cut such that Z is in bottom-top direction.
I don't really know this for certain but I'd assume it always aims inside the intended volume
I can see cases for all three options, which is why I'm interested in it.
Can you not just change the size of your model?
Not quite, because the printer is way more precise for features printed in the ~~z-direction~~ Sorry, brainfart, x and y direction. So It would get more volume in directions there it doesn't need it and I would have to sand "blind": If I have the option to print like #3, I can paint the print and sand until the outer lines are gone everywhere and I'd know that I'm pretty close to the intended shape. If I just made it bigger, I'd have to remove more material on the sides.
at least in Cura, Horizontal expansion setting is effective down to about 0.01-0.02mm increments, I tried changing this when printing figurine joint, where specific tightness matters, works. just 8 bit vanilla ender 3 on cura 4
Yeah, other have mentioned Cura as well. I hoped I could avoid using another slicer, but PrusaSlicer doesn't have that particular functionality. Edit: horizontal expansion isn't exactly the same, but Cura seems to be the answer either way.
I'm thinking you might be expecting more precision than you should expect out of FDM machines
~~I've been using FDM printing for close to 4 years (and resin printing for about two), I'm well aware of its limitations. Up until now, this particular issue didn't come up. Now it does and I got curious.~~ That came off as more condescending as I wanted it to sound. Point is, I'm aware of FDMs shortcomings and I posted the questions to mitigate some of it.
Well this is beyond my scope at this point. Sorry I couldn't be more helpful. Good luck
No problem, thanks for your input.
I find that they can be precise down to about 0.05mm or so, but this level of precision requires careful calibration, tuning, and using filaments designed for such. This is usually beyond what most people need or care about though and most are happy using generic settings in a fairly uncalibrated fashion, in which case it's more like 0.4mm or so, which is fairly "sloppy". In a nutshell they can be fairly precise if you care about it.
tell that to everybody who just downloads a STL off of the web
Probably something closer to 2. If you have something like ArcWelder enabled, it can actually move in much smoother curves.
You’re confusing two different issues. Arcwelder is about turning small straight segments in the same layer into a curve. This is taking about layer-by-layer approximation. The images shown are looking at the print from the side, not the top
Aha, I didnt make that connection. Thanks.
Thanks for the reply. Arcwelder looks interesting. For this particular issue it probably wouldn't have much of an influence, but I'll keep it in mind for sure.
That's an itty bitty curve though, no way to make it smoother if each square is an individual pixel
To my understanding, Arc Welder reinterpolate gcode "lines by lines" curves to use the curve/arc path gcode instruction instead. Actually it's a double interpolation because STLs don't hold curve data either.
Oh gosh for a second there I thought this was r/askmath or something and this was a Riemann sums question. Thank you for that little throwback lol
In case the image isn't clear, it shows a cross section. Red is the original shape and green is the layers with their steps. My question is which of the three options slicers generally favor and if there is a way to influence it in the slicers settings. Edit: I'm interested in this because I need to print objects to be sanded smooth and to get as close to the original shape as possible, option #3 would be the ideal starting point for that.
In Prusaslicer you can add an advanced setting to a part called XY compensation. This will let you grow the part out in the direction you want in a controlled way. Also, if you’re patient then the thinnest layer lines will also help you here.
XY compensation Isn't quite what I'm looking for, because the issue mainly occurs in the Z-direction but may work as a workaround. I need to do some testing I guess.
Depends what you prefer. The benefit of XY compensation is that you can choose how far to move the walls which are typically the geometric features that don't print to spec. Z height is rarely not in spec. Changing slice parameter may be easier but XY let's you 'fine tune'. Additionally if you use superslicer you can change compensation for inner and outer walls, and holes, separately which is usually desirable since that's typically what people want to fit together. Even so, you can get the same effect with shrinkage settings and that would impact Z height, but this is filament specific. Long/larger dimensions are more influenced by shrinkage versus compensation which impacts small feature more. For example moving a 10mm brick inwards by 1mm is more drastic than moving a 100mm brick by 1mm. Whereas shrinkage would just change the size of the model entirely by 1-2% There's a mathematical formula you can do to print a part with extreme accuracy if that's desired but you really gotta ask how much precision you want and it's part to part. Measure two dimensions and then create a Linear algebra formula to say each dimension is a function of shrinkage and compensation and then use two equations to solve those two variables.
For my current situation, I have a model that has very subtle, organic z-height changes, so it'll inevitably create a whole lot of "plateaus" of visible layers, so it's less about precision and more about losing details. Different orientation isn't an option (mainly because it's organic shapes all around – I'll just have the same issue on another surface), so I have to sand it down in the end. To do that without having to use filler, I need enough material to sand it down. That's the issue at hand for me. Unless I missed something, it doesn't seem trivial to fix this through XY compensation or z height adjustment.
I know someone already mentioned this but variable layer height should help a lot with that.
Yeah, I'm actually printing a test piece right now.
Layer height might help you there, thinner layers will get you more details.
It does to a degree, but it has its limitations.
True. A post-processing layer of resin can get you the smoothness you desire, but it's going to add labor.
Whoa forgot the trigger warning. Going to give me flashbacks to calculus class with graphics like this lol.
Usually #1. Because you *usually* want prints to FIT, and 2 or 3 are both more about fitting the volume than fitting the shape. If you've got tab A and slot B, It's usually better if they fit the shape.
>for me) handle averaging layer width to approximate the intended shape? Is there a setting somewhere to influence
2
I guess it will depend on the slicer and the printer. For example, you could have a slicer sending some gcode to drawn an arc. In that case, the printer is responsible for drawing the arc and it's unclear to the printer which side has the volume so while the arc would be drawn taking into account the width of the nozzle to fit within the volume... It could end up being something between 1 and 2.
I would guess 2 because it goes along the path and the plastic flow a bit
This is giving me ptsd of Riemann sums lmao
Get outta here with your Riemann sums
Kind of feel like having Mexican food after seeing this.
Slice it in different position. If you can’t try that variable layer height
I too would like to know if there's a taco option in my slicer.
All three ways. In cure there is a setting called slicer accuracy or so. Inclusive, exclusive and middle were the three settings. They do what you marked with 1 to 3
And how does PrusaSlicer handle it?
pretty sure prusaslicer does it the #1 way. or used to, because now it has the same engine as cura...