Geometry badly altered when slicing

#1

In some instances when the geometry gets “re-meshed” during slicing, new vertices are introduced that make the bottom surface of the part not flat hence pushing the model up one layer and throwing a warning. I have seen other posts with the same warning, but none of them mentioned the mesh changes.
BEFORE SLICING:

image
image.png1114x708 54.9 KB

WARNING MESSAGE:
image
image.jpg1029x406 85.6 KB

AFTER SLICING:
image
image.png1156x810 57.2 KB

THE FILE:
DASH_RIB.stl (669.1 KB)

I sliced the same file in Chitu, Lych, HALOT BOX, Preform, UV Tools, FlashDLP, and Anyc Workshop, and works with no issue.

#2

Hi,

I see from your screenshot you are using z-bleed correction of 0.15mm. That’s a lot.
It’s really a ‘use with caution’ function. If you use it on a simple mesh with relatively low vertex count you might see some strange deviations.

In general i’ve implemented the algoritm in a way that was comparable to netfabb back in the day. That means it ‘lifts’ up vertices before slicing. You can also just use the command from the menu to apply this correction and check what it does visually before slicing. (there’s an option to not modify vertices at the ground plane, so you wont get empty slices).

An alternative i’m contemplating was to apply the zbleed correction in pixels; but that would make slicing slower… and the correction won’t work in SLA printers…

It should revert back the mesh after slicing… so i’m surprised you see the mesh like this. That shouldn’t be and it’s something i need to check.

kind regards
Elco

#3

Thank you for the quick response and insight.
That amount of Zbleed seems to be just right to get horizontal round holes round. These are small1.5mm round wholes so any amount of bleed flattens them. That said, I always looked at it as a global resin tuning parameter, so your observation as a per mesh function is intriguing.
I look forward to what you come up with as a solution.
Thank you again,
Gonzalo

#4

Hello Elco, have you had any luck with this issue? I included a screenshot of the same .STL file loaded in Halot Box and in F3D, look at the difference! it is bad enough that shows on the printed surface…

image
image.jpg3830x2155 1 MB

#5

Hi gonzalo,

Is this when you apply z-bleed correction? (I think halot box doesn’t do that? )

Or is this when you load an STL without doing anything? If so please wetransfer me the STL at our info@ address.
And if the STL, what software do you use to generate the STL?

kind regards
elco