Having the model trained on how to construct triangles (rather than blobbly points) means that we're closer to a "take photos of a scene, process them automatically, and walk around them in a game engine" style pipeline.
Are triangles cheaper for the rasterizer, antialiasing, or something similar?
Older GPUs natively supported quadrilaterals (four sided polygons), but these have fundamental problems because they're typically specified using the vertices at the four corners... but these may not be co-planar! Similarly, interpolating texture coordinates smoothly across a quad is more complicated than with triangles.
Similarly, older GPUs had good support for "double-sided" polygons where both sides were rendered. It turned out that 99% of the time you only want one side, because you can only see the outside of a solid object. Rendering the inside back-face is a pointless waste of computer power. This actually simplified rendering algorithms by removing some conditionals in the mathematics.
Eventually, support for anything but single-sided triangles was in practice emulated with a bunch of triangles anyway, so these days we just stopped pretending and use only triangles.
A triangle by definition is guaranteed to be co-planer; three vertices must describe a single flat plane. This means every triangle has a single normal vector across it, which is useful for calculating angles to lighting or the camera.
It's also very easy to interpolate points on the surface of a triangle, which is good for texture mapping (and many other things).
It's also easy to work out if a line or volume intersects a triangle or not.
Because they're the simplest possible representation of a surface in 3D, the individual calculations per triangle are small (and more parallelisable as a result).
In fact, I belive that under the hood all 3d models are triangulated.
Yes, using triangles simplifies a lot of math, and GPUs were created to be really good at doing the math related to triangles rasterization (affine transformations).
So a gaussian splat scene is not a pointcloud but rather a cloudcloud.
A good way of putting it.
https://convexsplatting.github.io/
the seminal paper is still this one:
The problem is that any tool or process that converts splats into regular geometry produces plain old geometry and RGB textures, thus loosing its advantage. For this reason splats are (in my opinion) a tool in search of an application. Doubtless some here will disagree.
This ends up being very effective with interpolation between known viewpoints, and hit-or-miss extrapolation beyond known viewpoints.
Wouldn't this lead to the full 3D representation?
author = {Held, Jan and Vandeghen, Renaud and Deliege, Adrien and Hamdi, Abdullah and Cioppa, Anthony and Giancola, Silvio and Vedaldi, Andrea and Ghanem, Bernard and Tagliasacchi, Andrea and Van Droogenbroeck, Marc},
while on arxiv and the top of the page
Jan Held, Renaud Vandeghen, Adrien Deliege, Abdullah Hamdi, Silvio Giancola, Anthony Cioppa, Andrea Vedaldi, Bernard Ghanem, Andrea Tagliasacchi, Marc Van Droogenbroeck
the first one is SURNAME, NAME separated by "and"
the second one is NAME SURNAME separated by commas
The second one is easier to read by humans, but the first one makes it clearer what is the surname (which would be ambiguous otherwise, when there are composite names). But then again, the first format breaks when someone has "and" in their name, which is not unheard of.
As it stands, it certainly does not resemble readable or parseable english.
‘Better’ formats have been proposed but none have stuck nearly as well. It works, and there’s tooling for it.
author = {surname 1, first name 1 and surname 2, first name 2 and ...}
"and" is the separator.
When I first read "triangle splatting," I assumed Gaussians were just replaced by triangles, but triangles being aligned with geometry changes everything. Looking forward to seeing this in action in traditional rendering pipelines.
It's already noticeable that there doesn't seem to be one fits all approach. Volumetric feathered features like clouds will not profit much from triangle representation vs high visual frequency features.
There are various avenues for speeding up rendering and improving 3d performance of 3DGS.
it's surely a very interesting research space to watch.
https://arxiv.org/pdf/2410.20593
https://speedysplat.github.io/
another venue is increasing the complexity of the gradient function like applying Gabor filters
https://arxiv.org/abs/2504.11003
some many ways to adapt and extend on the 3dgs principles.
Although, the normals look pretty good in their example images, maybe you can get good geometry from this using some post processing? But then is a triangle soup really the best way of doing that? My impression is that this is chosen specifically to get a final representation that is efficient to render on GPUs. I haven't done any graphics programming in years, but I thought you'd want to keep the number of draw calls down, do you need to cluster these triangles into fewer draw calls?
Is there any work being done to optimize a volumetric representation of scenes and from that create a set of surfaces with realistic looking shaders or similar? I know one of the big benefits of these splatting techniques is that it captures reflections, opacity, anisotropicity, etc, so "old school" photogrammetry with marching cubes and textured meshes have a hard time competing with the visual quality.
Gaussian Splatting radically changed the approach to photogrammetry. Prior approaches to generate surface models, and mapping the captures to materials that a renderer would more or less rasterize with physically accuracy were hitting the ceiling of the technique.
NerF was also a revolution but is very compute intensive.
Even a browser, a mid range GPU, can render millions of splats at 60 frames per seconds. That's how fast it goes and less than a million dense scene can already be totally bluf the eye in most possible angles.
Splatting is the most advanced, promising and already delivered on the promise technique for photogrammetry. The limit is that can't do as much in term of modification to point clouds vs surface with great PBR attributes.
If you take these triangles, make them share vertices, and order them in a certain way, you have a mesh. You can then combine some of them into larger flat surfaces when that makes sense, draw thousands of them in one draw call, calculate intersections, volumes, physics, LODs, use textures with image compression instead of millions of colored objects, etc with them. Splatting is one way of answering the question "how do we reproduce these images in a way that lets us generate novel views of the same scene", not "what is the best representation of this 3D scene".
The aim is to find the light field that describes the scene, and if you have solid objects that function can be described on the surface of those objects. Seems like a much more elegant end result than a cloud of separate objects, no matter what shape they have, since that's much closer to how reality works. Obviously we need to handle volumetrics and translucency as well, but if we model the real surfaces as virtual surfaces I think things like reflections and shadow removal will be easier. At least gaussian splats have a hard time with reflections, they look good from some viewing angles, but the reflections are often handled as geometry [1].
I'm not arguing that it doesn't look good or that it doesn't serve a purpose, sometimes a photorealistic novel view of a real scene is all you want. But I still don't think it's the best representation of scenes.
It made so much sense to me: voxels with view dependent color, using eg. spherical gaussians.
I don't know how it compares to newer techniques, probably badly since nobody seems to be talking about it.
GPUs draw can draw 10,000's of vertices per draw call, whether they are connected together into logical objects or are "triangle soup" like this. There is some benefit to having triangles connected together so they can "share" a vertex, but not as much as you might think. Since GPUs are massively parallel, it does not matter much where on the screen or where in the buffer your data is.
> Is there any work being done to optimize a volumetric representation of scenes and from that create a set of surfaces with realistic looking shaders or similar?
This is basically where the field was going until nerfs and splats. But then nerfs and splats were such HUGE steps in fidelity, it inspired a ton of new research towards it, and I think rightfully so! Truth is that reality is really messy, so trying to reconstruct logically separated meshes for everything you see is a very hard way to try to recreate reality. Nerfs and splats recreate reality much easier.
https://github.com/user-attachments/assets/6008d5ee-c539-451...
(or https://github.com/datoviz/data/blob/main/gallery/showcase/s...)
I'll add it to the official gallery soon, with proper credits.
I'm more familiar with traditional 3D graphics, so this new wave of papers around gaussian splatting lies outside my wheelhouse.
Can anyone who read this suggest something to use to scan room geometry using camera only in real-time (with access to beefy NVIDIA computer if needed) for drone navigation purposes?
"Watertight" is a actially a stronger criterion, which requires not only a contigous surface, but one which encloses a volume without any gaps, but "not watertight" suffices for this.
dsp_person•1d ago
Go team triangles!
dr_dshiv•1d ago
franky47•23h ago