Hey Product Hunt 👋 I'm Yuta, the maker of Raildraft. Here's the problem. You spread Plarail track across the living room floor, build a big loop, and the last rail doesn't reach. Off by two centimeters. You force it together, the train hits that joint, the track pops apart. You start over. Every layout tool I could find answers "roughly like this." I wanted one that answers "does this actually connect?" **So Raildraft does the physics.** - Every part is at real dimensions — 216mm straights, R216/45° curves, ~37 rail types plus piers. - Real joints have play, and they flex a little when you push them. Raildraft models that as a dead-band elastic and solves the whole layout as a pose graph with Levenberg–Marquardt — the same math as loop closure in SLAM. Iteration count doesn't grow with layout size, so big layouts stay interactive. - You get numbers, not vibes: this joint is at 40% strain, that one comes apart. - When the loop won't close, it tells you the fix: "insert one Quarter Straight Rail, strain drops from 61% to 8%." One click to apply. - It's 3D, not a floor plan: slopes, piers, elevated track, overpasses, and clearance checks for the train to pass underneath. - Run a train through it, switch the points, get a parts list. **My favorite part:** enter what's actually in your box, tell it how much floor you have, and it builds layouts you can make *today* with the rails you own. (One tatami mat, 1,800 × 900 mm — the same size as the official Plarail contest.) No account needed to try it — layouts save in your browser. Log in only if you want them synced across devices or shareable by link. Free. Estimated dimensions are always labeled as estimated, and you can calibrate them against your own measurements in Settings. I'd rather say "I'm not sure" than quietly hand you a wrong number. Raildraft is an unofficial fan tool. Plarail is a registered trademark of Takara Tomy, and I'm not affiliated with them. Built with Next.js 15, React 19 and Three.js, on Hono + Drizzle + Postgres. The geometry and solver live in a pure TypeScript package with no DOM dependency, at 90%+ test coverage. I'd love to hear: what's the layout you could never get to close? → https://raildraft.app/en

Raildraft

Toy train layouts that actually fit together

Toy train layouts that actually fit together