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prusa3d / PrusaSlicer

G-code generator for 3D printers (RepRap, Makerbot, Ultimaker etc.)
https://www.prusa3d.com/prusaslicer/
GNU Affero General Public License v3.0
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Resin print - Autosupports - Slightly tilting the model changes the distribution of supports leading to failure #9423

Open apopanda opened 1 year ago

apopanda commented 1 year ago

Description of the bug

We're printing a large chunk of resin for a mold. We've oriented it on one of the thinner sides and used the Prusaslicer autosupport feature. It started creating supports correctly, although a little too close to the model, leading to marks on one of the mating surfaces. For the next print, we opted to tilt the model around 2 degrees away - the supports go straight up, so if we get any marks, it's not directly on a spot where sanding would cause flashing issues.

Actual: This caused most of the supports to move to the edge lowest to the print, incredibly cutting on the support density, causing the heavy block to fall away Expected: Additional support points are added without losing on the overall density of the supports.

It looks like there's a total number of supports on that face and tilting the model simply causes it to move most of them to the lowest edge, instead of generating more supports.

Project file & How to reproduce

You need the SLA supports feature, so choosing the printer as the original prusa SL1. I then changed the size of the bed to fit my Mono X 6k. I import the STL linked below. I click on the model to select it, I choose to autosupport it using the "auto generate points" feature.

The difference between the models, is that one has a 2 degree tilt, which shouldn't change the neccessity of the bottom being supported.

100% density tilted 2 degrees away: image 100% density straight up: image

bug_resin.zip

Checklist of files included above

Version of PrusaSlicer

Version: 2.5.0+win64 Build: PrusaSlicer-2.5.0+win64-202209060714

Operating system

Win10

Printer model

Anycubic Photon Mono X 6k

apopanda commented 1 year ago

Might be something to do with the fact that the 0 degree tilt is straight on the bed, so autosupports uses a different way of generating it, than if it's lifted off already?