web editor stl export

[pca006132]

It would be nice if we can directly export the model as a STL file, that way users can directly put it into a slicer. IIRC threejs already provides STL file exporter?

[elalish]

My issue with STL is it fundamentally can't transmit manifoldness (it has no connectivity info). I'd much prefer 3MF (partly because I helped develop it) as it solves this problem and I think most of the 3D printer slicers import it now.

[hrgdavor]

I started to clean it up a bit. https://github.com/hrgdavor/jscadui/tree/main/file-format/3mf-export

the minimum needed to produce a 3mf is relatively simple. It supports instancing, but unfortunately slicers like prusa do not respect it.

[elalish]

Excellent, thank you! When you say prusa does not respect instancing, what do you mean?

Do you plan to publish this to npm so we can take a dependency, or should we fork your code into our repo?

[hrgdavor]

When you say prusa does not respect instancing, what do you mean?

I had a questionable use-case where I used multiple instances of a cube to produce a shape without doing boolean union. Prusa slicer does not then use those instances as a single model, but as separate entities and drops them all to the plate. I posted a bug report on prusa git. They were not willing to fix, then I told them "screw you" and closed the ticket ... not one of my finest moments :D.

details: prusa3d/PrusaSlicer#7078

Do you plan to publish this to npm so we can take a dependency, or should we fork your code into our repo?

The code was part of a quick prototype and messy. I finally started oragnizing the code so it is more easily reusable. I will publish it as npm package, and also put an example how to use fflate to create the actual zip file. fflate will intentionally be dev-dependecy so ppl using the 3mf lib can use their preferred zip library.

[elalish]

Ah, I see why they do that - well the good news is Manifold should take care of that problem nicely. Sounds like a good plan - any idea how long you think it'll take to get to a first npm release?

[hrgdavor]

I should have it tomorrow. I already have a npm acc and publishing my small libs regularly.

[pca006132]

That's fine either, as long as it can export something that can be imported by 3D printer slicers.

[Loosetooth]

I'd also be really interested in a (built-in or not) export mechanism that:

1. is compatible with slicers
2. keeps manifoldness

Having recently had a bit of a struggle with manifoldness problems, because of exporting in STL format, I think this would be an ideal addition to manifold.

@hrgdavor Could you share a link to your prototype 3mf code? Thanks.

[Loosetooth]

For the time being, when using three.js:

the OBJExporter seems to work pretty well.

[hrgdavor]

Initial step of cleaning up the 3mf code I had in my prototype is done.
it is now published on npm https://www.npmjs.com/package/@jscadui/3mf-export
and code is at
https://github.com/hrgdavor/jscadui/tree/main/file-format/3mf-export

it is now something that should work, but still has cleaning to do and documenting jsdoc types