How does per-model layer sizing work?
It looks like I can assign custom layer sizing to models different than what is set in 'print settings' for the whole plate. How does this sorcery work?
For example if the plate it set to 0.1 and I set one model (which doesn't need as much precision) to 0.2, does the print head still move up in 0.1mm increments, and just skip the less precise model on the even numbered layers, and extrude twice as fast when it's on that model?
What happens in the inverse, if one model is set more precise?
and just to be curious, if I use randomly chosen prime numbers for layer heights does it try to factor those to come up with the least common denominator?
Best Answer by Neophyl:
For example if you have one model set to 0.2mm layer height and a second set to 0.1mm it will extruder 2 layers on the 0.1 model then 1 layer on the 0.2mm model, then 2x 0.1 on the other. Luckily the slicer sorts it all out for you and the printer just blindly follows the clever gcode produced.
With more complex layer heights (such as if you used variable layer heights on 2 different models) it just prints the next highest layer in the queue. Yeah it'll do more zipping around between models but thats the price you pay for using different layer heights.
The other thing to remember is that if you are using support then its doing that anyway as support layer height is not tied to the model layer height at all.
RE: How does per-model layer sizing work?
My understanding of layer height is that it is the thickness of each layer. 0.2 is standard for 0.4mm nozzle. The smaller the nozzle height, the more precise the print but also takes more time to print. 0.8 layer height will print much faster than 0.2.
If you adjust it per model, it will adjust up and down when it gets to each print and it is noticeable on larger prints.
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Chuck H
3D Printer Review Blog
RE: How does per-model layer sizing work?
For example if you have one model set to 0.2mm layer height and a second set to 0.1mm it will extruder 2 layers on the 0.1 model then 1 layer on the 0.2mm model, then 2x 0.1 on the other. Luckily the slicer sorts it all out for you and the printer just blindly follows the clever gcode produced.
With more complex layer heights (such as if you used variable layer heights on 2 different models) it just prints the next highest layer in the queue. Yeah it'll do more zipping around between models but thats the price you pay for using different layer heights.
The other thing to remember is that if you are using support then its doing that anyway as support layer height is not tied to the model layer height at all.
RE: How does per-model layer sizing work?
Excellent! So it sounds like I should avoid my intentionally wacky example of random layer heights, and if I use different ones at all, keep them doubles or halves.
I have a part that I need to print and my usual, 0.2, did not have the fidelity I would like. But I also have a bunch of lower-importance stuff to print. I get one timeslot to use the prusa each week so I'd like to craft one job that uses that time, and build plate, to its fullest.
RE: How does per-model layer sizing work?
Sounds like you could set the default layer height to be as 'coarse' as you can get away with for the low details sections/parts and then use the variable layer height tool to make the sections that need it have a thinner layer height. One tip is to set the Min Layer height value located in Printer Settings > Extruder to the most finely detailed layer you want as the variable layer height tool uses the min/max defined under the extruder settings.
I often find myself only wanting to go as low as 0.1 on most parts using the tool so changing the extruder setting to that acts as a limit.