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Show HN: Real-Time Gaussian Splatting

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Re: Show HN: Real-Time Gaussian Splatting

#22

Another implementation of splat https://github.com/NVlabs/InstantSplat

Note that the method you linked is "Splatting in Seconds" where as real-time requires splatting in tens of milliseconds.

I'm also following this work https://guanjunwu.github.io/4dgs/ which produces temporal Gaussian splats but takes at least half an hour to learn the scene.

Re: Show HN: Real-Time Gaussian Splatting

#24

So, I see livesplat_realsense.py imports livesplat. Where’s livesplat?

I've tried to make it clear in the link that the actual application is closed source. I'm distributing it as a .whl full of binaries (see the installation instructions).

I've considered publishing the source but the source code is is dependent on some proprietary utility libraries from my bigger project and it's hard to fully disentangle it and I'm not sure if this project has some business applications but I'd like to keep that door open at this time.

Re: Show HN: Real-Time Gaussian Splatting

#25
Gaussian Splatting looks pretty and realistic in a way unlike any other 3D render, except UE5 and some hyper-realistic not-realtime renders.

I wonder if one can go the opposite route and use gaussian splatting or (more likely) some other method to generate 3D/4D scenes from cartoons. Cartoons are famously hard to emulate in 3D even entirely manually; like with traditional realistic renders (polygons, shaders, lighting, post-processing) vs gaussian splats, maybe we need a fundamentally different approach.

Re: Show HN: Real-Time Gaussian Splatting

#26
post #18

Earlier quoted context omitted.

Yes, the normal case uses 2D input, but it can take hours to create the scene. Using the depth channel allows me to create the scene in 33 milliseconds, from scratch, every frame. You could conceptualize this as a compromise between raw pointcloud rendering and fully precomputed Gaussian splat rendering. With pointclouds, you have a lot visual artifacts due to sparsity (low texture information, seeing "through" objec…

How do the view-dependent effects get "discovered" from only a single source camera angle?

Actually there are multiple source cameras. The neural net learns to interpolate the source camera colors based on where the virtual camera is. Under the hood it's hard to say exactly what's going on in the mind of the neural net, but I think it's something like "If I'm closer to camera A, take most of the color from camera A."

Re: Show HN: Real-Time Gaussian Splatting

#27
Correct me if I'm wrong but looking at the video this just looks like a 3D point cloud using equal-sized "gaussians" (soft spheres) for each pixel, that's why it looks still pixelated especially at the edges. Even when it's low resolution the real gaussian splatting artifacts look different with spikes an soft blobs at the lower resolution parts. So this is not really doing the same as a real gaussian splatting of combining different sized view-dependent elliptic gaussians splats to reconstruct the scene and also this doesn't seem to reproduce the radiance field as the real gaussian splatting does.

Re: Show HN: Real-Time Gaussian Splatting

#28

Earlier quoted context omitted.

I know enough about 3D rendering to know that Gaussian splatting's one of the Big New Things in high-performance rendering, so I understand that this is a big deal -- but I can't quantify why, or how big a deal it is. Could you or someone else wise in the ways of graphics give me a layperson's rundown of how this works, why it's considered so important, and what the technical challenges are given that an RGB+D(epth?)…

Gaussian Splatting allows you to create a photorealistic representation of an environment from just a collection of images. Philosophically, this is a form of geometric scene understanding from raw pixels, which has been a holy grail of computer vision since the beginning. Usually creating a Gaussian splat representation takes a long time and uses an iterative gradient-based optimization procedure. Using RGBD helps m…

So, is there some amount of gradient-based optimization going on here? I see RGBD input, transmission, RGBD output. But, other than multi-camera registration, it's difficult to determine what processing took place between input and transmission. What makes this different from RGBD camera visualizations from 10 years ago?

Re: Show HN: Real-Time Gaussian Splatting

#30
post #27

Correct me if I'm wrong but looking at the video this just looks like a 3D point cloud using equal-sized "gaussians" (soft spheres) for each pixel, that's why it looks still pixelated especially at the edges. Even when it's low resolution the real gaussian splatting artifacts look different with spikes an soft blobs at the lower resolution parts. So this is not really doing the same as a real gaussian splatting of co…

I had to make a lot of concessions to make this work in real-time. There is no way that I know to replicate the fidelity of "actual" Gaussian splatting training process within the 33ms frame budget.

However, I have not baked in the size or orientation into the system. Those are "chosen" by the neural net based on the input RGBD frames. The view dependent effects are also "chosen" by the neural net, but not through an explicit radiance field. If you run the application and zoom in, you will be able to see the splats of different sizes pointing in different directions. The system as limited ability to re-adjust the positions and sizes due to the compute budget leading to the pixelated effect.

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