Opus 5.5 helped me build Tokyo in the browser with Three.js by compiling open data - PLATEAU's 3D city model, OpenStreetMap and GSI elevation and aerial photos into streaming tiles, with procedural shader facades, generated road markings, signal-obeying traffic and trains. Also added Takram's volumetric clouds which cast shadows... on the streets.show more

Source code:

@threejs how are the different source datasets aligned at tile boundaries? a route crossing a seam seems like a useful test for elevation offsets, road continuity, and traffic handoff, especially when adjacent tiles arrive at different times.

@threejs Good test idea! Tile seams turned out fine by design: elevation is one global 5 m grid and the road graph is global, so there's no handoff between tiles. But your question led me to a real handoff bug: cars leaving a flyover dropped to the ground under the ramp. Fixed now 🙏

@threejs Cloud shade sliding across real neighborhoods sells the whole thing. Pulling public mapping sets into something this smooth is a serious amount of plumbing, and it shows.

@threejs love it! i have this on my list to try with blender then export to unity

@threejs looking forward to it!

@threejs This makes me want an 'under the hood' toggle: buildings, terrain, roads, then the finished city. Seeing what each public dataset contributes could be almost as interesting as exploring Tokyo.

@threejs looks good

@threejs But it might be slow, I only test it on 5090 :)))))) Anyway, we can try to improve it

How did the PLATEAU buildings line up with the GSI terrain? Curious whether the heights matched directly or needed corrections around the building bases.

They matched directly: both PLATEAU and the GSI elevation tiles give heights above Tokyo Peil (the Japanese vertical datum), so no datum correction was needed, only small fixes at the bases. Shibuya is worse because it is hilly: a building on a slope has one base height but the ground under it varies by a meter or two across the footprint. Base height comes from PLATEAU, not the terrain. Each building sits at the lowest point of its own LOD1 solid. Only buildings with no solid fall back to the terrain height.

@threejs これはすごい。 試してみましたが本当に構築できてました。 これを活用していろんなことができそうです。

@threejs Signal-obeying traffic is the detail that sells it. Everything else is just buildings.

@threejs how much tokens did you used to make this possible?

@threejs 3 hours of work, haven’t paid too much attention on token usages :)

@threejs I like it. Open data into a living Tokyo.

@threejs Very good !