3MF Production Extension support

[Floppy]

Description

The 3MF loader does not currently load models that use the 3MF production extension.

Solution

When a 3MF file using the extension is loaded, It would be great to be able to successfully load and display them, even if all the production features were ignored. Currently nothing is loaded.

Alternatives

No alternatives that I can think of, other than asking users to save files without the extension, but that's not ideal in my application, which is based around 3d print models.

Additional context

I need to look into it a bit to see exactly how it fails, and I might be able to spend some time on this soon, but I'm opening this in case anyone has already done it, is planning to, or already knows how to.

[Mugen87]

Related: https://discourse.threejs.org/t/why-my-3mf-model-can-not-load-and-render-by-threemfloader-and-report-a-error-pls-help/73336

At the discourse topic, there is a 3MF asset attached which can be used for testing.

[Floppy]

Ah, nice. I've got some at manyfold3d/manyfold#2438 as well.

[Floppy]

Also, pinging @kf0302 for reference!

[TechJeeper]

Following. Having the same issue Thank you!

[Jack-J-Young]

I had the same issue so I had a look into it, the issue is the order that the objects are built inside the loader, it builds them in the order it finds them in the 3mf archive which means dependencies might be referenced before they are loaded
A fork with a simple fix

There's definitely better methods, entirely changing how the build is ordered or at the very least having a custom error for unloaded resources, might look further into it

[Floppy]

Oh, wow, great find!

[Jack-J-Young]

Found a simpler solution and created a PR, only the root model can contain the external references that are causing issues so building that last fixes it

[Floppy]

@Jack-J-Young that's great! I will port this into my forked webworker version at https://github.com/manyfold3d/threejs-webworker-3mf-loader, unless you'd prefer to open a PR there yourself, for the commit credit?

[Jack-J-Young]

@Floppy I don't mind, you can port it