July 26, 2026
Holy scroll wars
Building the Grace Cathedral Experience
A stunning virtual church tour drops—and the comments go from holy awe to laptop panic
TLDR: A team turned Grace Cathedral into an interactive online tour that runs right in the browser, aiming to make a huge, detailed 3D scene feel smooth on many devices. Commenters were split between being moved by the atmosphere and annoyed that the embedded demo hit some computers so hard it got in the way of reading.
San Francisco’s Grace Cathedral just got the full digital celebrity treatment: a gorgeous browser-based tour that lets people wander around the famous church, peek inside its walls, and soak in the atmosphere without leaving home. The builders are clearly proud of the behind-the-scenes wizardry that makes it load fast and work on phones and desktops, but honestly? The real sermon happened in the comments.
One camp was completely enchanted. The most heartfelt reaction wasn’t even about graphics—it was about the choir music. One commenter loved hearing a psalm in the old Anglican choral style, which instantly turned the demo from “cool tech” into “whoa, this actually feels sacred.” That same person also dropped the wonderfully awkward observation that, after spending time in churches like this, it felt weirdly wrong to stroll right up to the altar in a virtual tour. Peak internet: one minute admiring digital craft, the next confessing simulated cathedral guilt.
Others treated it like a sequel fans were already tracking, with one commenter linking the earlier Show HN post like this was the latest episode in an unexpected church-tech franchise. Then came the practical crowd: one newbie asked if this could be done for their own house, basically turning a grand cathedral showcase into a DIY real-estate fantasy. And the spiciest complaint? A user flatly said embedding the app in the page was a bad idea because their PC choked so hard they couldn’t even read the article. So yes, the demo impressed people—but it also sparked the timeless online debate: beautiful experience, or browser hostage situation?
Key Points
- •The article explains how a browser-based interactive 3D experience of Grace Cathedral was built from Vincent Woo’s Gaussian splat capture.
- •The project uses the PlayCanvas Engine with a WebGPU hybrid renderer and automatically falls back to WebGL 2 when needed.
- •WebGPU compute shaders perform per-frame culling, projection, and sorting of active Gaussian splats on the GPU, improving performance over the earlier CPU-worker WebGL 2 approach.
- •Splat assets are delivered in streamed SOG format with chunked levels of detail, separate interior and exterior sets, and progressive loading tuned for time-to-first-pixel.
- •Performance features include on-demand rendering, resolution caps, depth pre-pass occlusion, and a Peek effect implemented through gsplat shader chunk customization.