alt.hn

7/20/2026 at 8:10:44 PM

Show HN: Immersive Gaussian Splat tour of grace cathedral, San Francisco

 https://vincentwoo.com/3d/grace_cathedral/

by akanet

7/20/2026 at 11:18:19 PM

From OP's prior work scanning Sutro Tower in SF: https://vincentwoo.com/2025/02/18/sutro-tower-in-3d/.

> This scan is made possible by recent advances in Gaussian Splatting. This is an emerging technology that lets us quickly create very detailed models just from photographs. For this model (or splat, as we call them), my friend Daylen and I flew our drones around Sutro Tower at a respectful distance for an afternoon until we had collected a few thousand photographs.

> I then aligned these pictures in free software called RealityCapture. Alignment is the process that teaches the computer that a bunch of points in different images all actually correspond with the same point in real life. Then I used another piece of free software called gsplat to produce the 3D model itself.

I'm assuming this was done similarly. Very cool.

by wxw

7/21/2026 at 12:33:40 AM

Yes, I also added a bit of context on twitter (https://xcancel.com/fulligin/status/2079296985811873796) and will probably blog about the process a bit more. Grace was a lot more work than Sutro. I wanted to be ambitious in combining interior/exterior scenes in a new way, and I also wanted it to be less of a "toy". Grace actually plans to use this to show prospective renters the space, and we spent a lot of time making sure it could run well on a wide variety of devices.

by akanet

7/21/2026 at 1:15:12 AM

Beautiful work, thank you for sharing it!

In case it's useful, given your last sentence, it runs really well on Chrome on Android (on a Pixel 10) but it's a bit glitchy (although not impossible) on Firefox on Android. The loading indicator on Chrome got stuck briefly whereas the Firefox one was smoother, but that's about the only case there Firefox is better.

by nmstoker

7/21/2026 at 2:36:00 AM

FWIW, it works great in Firefox focus on an iPhone 16 Pro.

by Hnrobert42

7/21/2026 at 12:49:46 AM

So beautifully done, its mindblowing. Please blog about your process a bit more.

by skanga

7/21/2026 at 3:30:57 AM

absolutely beautiful. I'd love to learn this process and attempt to capture a local rock climbing route.

anything you write about the process, or how you learned are very welcome.

by schaefer

7/21/2026 at 8:36:03 AM

The cathedral is the star of the show, but I found myself more fascinated by all the incidental little details captured in this. Like the trees and the buildings nearby, the basketball court, the little solar panel on the side, the apartment towers.

It's like seeing the promise of Google Street View realized.

The technology is in such an early stage and it already slaps this hard.

Wonder what the next steps are for this tech? "Un-splatting" optimizations to convert things like flat surfaces into classic rigid textured geometry? Factoring the lighting away from the geometry? Filling the pipeline with AI tooling - segmentation to remove the "variables" like humans automatically, generative AI to fill in the missing non-semantic details based on the surroundings, more generative AI to "port" the data from things like public high resolution images of plaques or other undercaptured details into the scene?

Seeing this kind of reconstruction now makes me very excited for what the 3D environments of the future are going to be like.

by ACCount37

7/21/2026 at 8:52:32 AM

One other little easter egg you may not have noticed. There's an American flag gently fluttering in the breeze on top of a nearby building. We were discussing whether to adds some birds as well, but that never made the final cut. You ask about factoring lighting away from the scene - actually, PlayCanvas can already do relighting and shadow-casting for gaussian splat-based scenes:

https://playcanvas.com/examples/#/gaussian-splatting/relight...

Some kind of day/night toggle would have been another great feature...but again, it didn't make the final cut of the experience. Maybe a HD Remix is needed. :o)

by ovenchips

7/21/2026 at 8:49:43 AM

Apple (“streets”) Maps uses that tech in the latest beta. (Apple Maps is generally better than google maps apart for the data, tbh)

by frizlab

7/21/2026 at 10:10:11 AM

I had a bit of an amusing time trying to see if I could find my apartment. I could though it was quite blurry :)

by saagarjha

7/21/2026 at 5:31:18 PM

It’s beautifully done. A few questions

I noticed that complex patterns - marble, some paintings, some stained glass - are rendered in what seems like stretched, hazy ellipses. Is that the fundamental building block of a splat?

Also, I was interested if any specularity would be captured by the splat. Or any other aspect of the building which shifts from viewpoint - like lights reflected on the marble floor, or where a metal element outdoors is reflecting the sun but only from one vantage point. I didn’t see that. As I understand it, splats are a kind of solution to the “problem” posed by the series of photos so they are capable of capturing that sort of thing. Is that present here, and I missed it? Or is that something that you need a lot of processing power for, to generate a more complex solution for the light fields?

by neilk

7/21/2026 at 8:24:12 PM

Splats can indeed come with view dependent colors to represent lighting, reflections… Those are captured in values called spherical harmonics of different levels 0, 1, 2, 3 representing different aspects like diffuse, directional lightning, highlights… Not all splat reconstructions come with spherical harmonics though. And they add rendering overhead.

Besides spherical harmonics splats are also good at representing high frequency detail that is harder with traditional meshes: Hair, clouds, vegetation… notice how trees in these reconstructions already look much better than in google maps / earth 3D views.

by dmarcos

7/21/2026 at 5:38:49 PM

The ellipsoids are what a splat renderer uses as primitives, usually.

by nnevatie

7/21/2026 at 12:21:08 AM

Reminded me of a VRML demonstrator inside Notre Dame from decades ago. Different approach, similar outcome. (it used surface texture mapping inside a game engine from my memory)

A lot more architecture would benefit from being available like this splat model. The Pharonic tombs which you can visit in google/other virtual tourism are good, but this is also good!

by ggm

7/21/2026 at 6:25:42 AM

Gsplat is indeed the future for graphics. Handling much more detail in mobile hardware spec. Check this work too. (Not mine) https://demo.immersivetech.ch/chateau-la-sarraz/

by suejunghuh0

7/21/2026 at 7:55:10 AM

Gsplat + dlss

by XCSme

7/21/2026 at 6:30:06 AM

The Peek mode is insanely good, it reminds me of those exploded views of buildings and "how things work" children books.

The model seems to be having a hard time with the marble floor in the quire (low resolution), is this because of its reflection?

by franky47

7/20/2026 at 10:38:48 PM

Very impressive. How are you managing to produce such a clean model without artifacts?

by squidsoup

7/21/2026 at 12:31:15 AM

I spent a lot of time hand-masking out inconsistencies between shoots. I waited too long between sessions and they actually built out an entirely new section of ceiling. PPISP guidance in splatting also helps a lot in solving sensor inconsistencies between the many different cameras and lighting conditions that went into the source dataset.

by akanet

7/21/2026 at 2:52:58 PM

Do you see potential for automation based on what you learned from your hand tuning?

by djmips

7/21/2026 at 12:24:40 PM

I'm not sure why, but my brain always gives a strong "this is not real" alert with Gaussian splats. Something about the lighting is really off for me.

And whenever I see videos explaining the Gaussian splats, they always claim they are supposed to fix lighting issues.

Is this a function of "not enough detail" or.. Something else?

by bubblegumcrisis

7/21/2026 at 12:41:36 PM

I think it's probably more like an "incorrect" focal length for what you'd expect. And it's kind of hard to know what you'd expect because you don't typically have arbitrary spatial control over your point-of-view, so some POVs you're used to only seeing through cameras (or even certain types of cameras), while others you're mostly used to seeing through your own eyes.

I imagine all of this will get better though.

by estearum

7/21/2026 at 1:55:05 PM

Interesting, thanks for the reply.

by bubblegumcrisis

7/21/2026 at 3:45:28 PM

[dead]

by wanick

7/21/2026 at 3:58:49 PM

This is fabulous. It captures the feeling of being in the cathedral quite well - it fully transported me back to that spot. Great work!

by holoway

7/21/2026 at 5:05:02 AM

Did you animate the cars separately? That really did a lot to add to the immersion (and the sound effects too). If nothing moved I think the effect would be significantly diminished.

by hankbond

7/21/2026 at 8:45:25 AM

Yes, the cars are separated out and procedurally animated. They're splats, like the rest of the scene. Easily done in PlayCanvas - simple but effective!

by ovenchips

7/21/2026 at 3:33:05 PM

It's the next day and I'm still thinking about how much of a difference that small touch made.

by hankbond

7/21/2026 at 3:16:24 PM

- top tier work

- let us say i wanted to bring a city to life like this

- what does the procedure look like on my end

- what inputs, tools, libraries would i need to go about doing this?

by vivzkestrel

7/21/2026 at 5:32:26 PM

I imagine it is based off World Labs

by bytesandbits

7/21/2026 at 5:27:17 PM

[dead]

by slickytail

7/21/2026 at 3:18:17 AM

Looks good the few seconds it works here. Then stops working and I have to close the tab and reopen for it to work again for another few seconds.

Firefox, Windows 11, Nvidia

Get the following in the console when it stops working:

  Uncaptured WebGPU error: Buffer binding 2 range 138024504 exceeds `max_*_buffer_binding_size` limit 134217728
  Uncaptured WebGPU error: Buffer binding 1 range 138024504 exceeds `max_*_buffer_binding_size` limit 134217728
  Uncaptured WebGPU error: In a set_bind_group command, caused by: BindGroup with '' label is invalid

by magicalhippo

7/21/2026 at 4:41:35 AM

Totally hung my Windows 11 machine with Firefox and 32GB of RAM. Ryzen 8745HS (Radeon 780M iGPU).

by gblargg

7/21/2026 at 4:18:11 AM

It looks like a webgpu driver issue - can you tell me what model of graphics chip you're using?

by akanet

7/21/2026 at 6:51:56 PM

RTX 5090 with 610.62 drivers, Windows 11 25H2, Firefox 153.0b9.

FWIW I tried the other one linked here[1] which also throws the same error and stops. Using the same engine perhaps?

[1]: https://news.ycombinator.com/item?id=48986175

by magicalhippo

7/21/2026 at 2:24:34 PM

Combining the interior and exterior captures sounds like the hard part. How did you get the two sets registered to each other?

by satoyoshidev

7/20/2026 at 11:03:22 PM

Extraordinary. Thank you for sharing. If there would ever be the possibility of seeing European Gothic cathedrals in this manner, that would also be really cool.

by julienchastang

7/20/2026 at 10:15:51 PM

Hi Vincent, the Sutro Tower 3dgs demo is one I enjoyed a lot. I'd whip it out on my phone and show people saying, 'hey look this is whats possible with 3D Gaussian Splatting'. And this Grace Catherdral splat is stunning. It showcases one of my favorite parts of 3dgs which is reflections and glass. The color and essence of the stained glass comes through so well.

The cutaway Peek feature is like a sci fi version of an Stephen Biesty's Incredible Cross-Sections book. Incredible work!

by hdz

7/21/2026 at 12:31:31 AM

Thank you!

by akanet

7/21/2026 at 12:57:53 AM

Wow Did you have any apps in Apple Vision Pro?

by asd000hh

7/21/2026 at 3:27:07 AM

I like the moving cars. They're copies of the stopped ones right? Adds a good effect.

by joegibbs

7/21/2026 at 8:42:24 AM

Yes. They're Gaussian splats like the rest of the scene. PlayCanvas has a global sort so they render correctly regardless of camera angle.

by ovenchips

7/21/2026 at 3:29:19 AM

This is such a cool immersive experience on mobile that works so well. Great job on this!

by petarb

7/21/2026 at 7:56:22 AM

Woaah, zooming all the way out is really cool

by XCSme

7/21/2026 at 2:13:24 AM

The cars moving in the beginning is a nice touch.

by umko21

7/21/2026 at 10:18:39 AM

That's really cool

by hacker_nows

7/20/2026 at 11:20:03 PM

absolutely crazy level of detail... in awe

by bytesandbits

7/21/2026 at 9:54:52 AM

what kind of drones did you use for this.

by asadm

7/21/2026 at 5:05:55 AM

Unreal. It’s been years since I’ve been here. It’s crazy the fidelity you can capture. Stunning work.

Unrelated silly question. Are you the same Vincent Woo who went over the whole unit combination story on Medium of a supervisor?

by arjie

7/21/2026 at 7:07:12 AM

Wow that's crazy that they built an apartment building where it would shadow all that stained glass.

I bet there's a story there.

by adaml_623

7/21/2026 at 2:07:47 AM

The Keith Haring altarpiece is a really cool surprise!

It's unfortunate that this tour makes it very difficult to see. Really not a fan of this "on rails" presentation style. I understand the angles matter when viewing a splat, but come on.

by sublinear

7/21/2026 at 3:12:31 AM

You can also walk freely FPS style with WASD and mouse-dragging to look around.

by rspeele

7/21/2026 at 6:55:48 AM

I only ever look at HN on a phone, and I'm pretty sure I'm in the majority.

Bad mobile support is a sore spot for any "Show HN" announcement.

by sublinear

7/21/2026 at 10:18:03 AM

Hello, I'm wondering whatever you mean? You can absolutely walk around the church indoors on mobile. Just tap to walk.

by slimbuck

7/21/2026 at 10:45:24 AM

(And if that doesn't work for you, please let me know!)

by slimbuck

7/21/2026 at 11:46:32 AM

[dead]

by swn21

7/21/2026 at 4:14:33 AM

Wow, I didn't expect to see transsexual steps in front of a church.

by xdennis