Allow selecting SPZ version when converting PLY → SPZ (engine rejects v3)

[popomore]

I’m converting a .ply Gaussian Splat to .spz using compress-to-spz.js / spz-js, and my engine fails to load the result with the following error:

Error: Unsupported SPZ version: 3
    at new SpzReader (b29a3111-679d-4c2d-ba77-ee2896492e3c:5015:15)
    at unpackSpz (b29a3111-679d-4c2d-ba77-ee2896492e3c:5750:17)
    at onMessage (b29a3111-679d-4c2d-ba77-ee2896492e3c:5584:27)
    at initialize (b29a3111-679d-4c2d-ba77-ee2896492e3c:5864:7)

From Niantic’s SPZ spec, the header version currently supports 2 and 3, and v3 changes how rotations are encoded vs v2. Some readers (including ours) only support v2 right now. Could you please advise how to force the converter to emit SPZ v2? (e.g., an option like serializeSpz(gs, { version: 2 }) or a CLI flag)

[dmarcos]

What viewer are you talking about? Is it based on spark?

If you want to use old spark code path can always checkout branch of previous versions. 0.1.8 version for instance https://github.com/sparkjsdev/spark/tree/v0.1.8

Does that work?

[dmarcos]

@popomore using the older version worked for you?