playcanvas
[Feature Request] 3D Gaussian Splatting MCMC support
It would be awesome if Markov Chain Monte Carlo is supported. PostShot just added support and the results are MUCH better. I actually tried loading MCMC ply file inside SuperSplat but it doesn't really show anything, just what seems a bunch of very distant splats. Tried compressing it and loading inside Playcanvas and it does in fact load but it looks like a complete mess.
Hi @equilento,
From a quick search I wasn't able to find an example file for MCMC GS.
If you are able to provide an example file then I can investigate the issue.
Thanks!
Hi @equilento,
This file is actually loading fine. The issue is there are very large splats far from the center of the scene. (So the camera is initialised far away to frame everything).
Here is a quick video showing how I select the very far away splats using the new DATA panel:
https://github.com/user-attachments/assets/09eebf17-022f-4939-a2d8-d6e3404fbd56
After deleting the large splats the scene flickers still in supersplat. I will fix this issue next.
Yeah, not only does it flicker but it is a mess. This is another model MCMC and "regular" GS in comparison.
Hi @equilento,
Sorry I don't understand what is being shown in the screenshot above.
Is the bottom image an MCMC scene loaded in Supersplat or...?
Yes, the bottom one is MCMC scene after I did the clean up like you showed. I tried loading it inside the editor and the results are the same.
Ah, right. Can you send me the original GS scene and instructions on how to replicate this issue?
Ok so I stumbled on something quite interesting. After I deleted far-away unnecessary splats like you suggested, focused on the model and zoomed in I get something that looks very bad (fig. 1) BUT after I then compress it, save it and open it again inside SuperSplat I get a model that looks much better (fig. 2) but still not as good as it is supposed to look like (fig. 3)
Uncompressed/unedited file: https://easyupload.io/gdbt1n
Hi @equilento,
Thanks for this!
The issue with the flickering is that deleted splats are not actually removed from the scene, they are just made transparent. This means the sorter buckets still include all splats, even though they're deleted. (We perform a very fast bucket sort for performance reasons).
I am busy updating the engine to support quickly removing deleted splats from sorting and rendering. This removers the flickering (equivalent of saving and reloading the scene) and speeds up the scene as you edit.
I will double check with the scene you gave me, but seems like it's the same issue.
Thanks again!
BTW for your testing, it's probably better to save the cut-down scene and then load that instead of saving a compressed version of the scene (since compression is lossy). Only the save the compressed version for runtime use.
I tried cutting down the original, saved the uncompressed file, reloading and then compressing it, opened it and it seems fine now. Couple of days ago I tried just compressing the original and I put it inside PlayCanvas editor and the flickering was present, even though I haven't done any editing. Why would that be? If I understood you correctly this shouldn't happen. Anyway this seems like a quick fix for me for now. Don't know how this would be reflected on bigger scenes.
Thank you for this!
