Planet Builder

Planet Builder hands you a globe and a brush. Pick a base, paint oceans and mountains and forests straight onto the turning sphere, set the atmosphere and the climate, and watch the habitability score tell you honestly whether anything could live there. A REAL GLOBE The planet is not a picture. The map you paint wraps a latitude and longitude grid that is projected onto a sphere, lit from one side and slowly rotated, so you see a real terminator and a real curve. Painting is inverted through the same projection: the cell under your finger is the one that changes, even while the world turns. Pause the spin to work carefully, or paint on the move. CLIMATE THAT DOES SOMETHING Temperature sets the snow line, and the ice caps follow it - warm the world and the caps retreat, cool it and the seas freeze from the poles down. Atmosphere density adds greenhouse warming on top of what you set, so a thick sky can push a temperate planet into a runaway. Humidity and weather set the cloud cover, and dry air browns the forests. None of it is decoration; the survey screen shows every number. SIX BASES Terran, Ocean, Desert, Ice, Volcanic and Barren. Each seeds a different surface from layered noise - continents, islands, dune fields, frozen seas, young mountain chains, or airless rock waiting for a builder - and a different starting climate. From there it is yours. HABITABILITY The score is built from sweet spots, the way a survey team would think about it: a surface near 18°C, oceans covering about half the globe, air near Earth density, moisture enough for forests, and as little ice and desert as possible. The survey explains the verdict in plain words, from "colonists would queue for this" to "a research outpost at best". IN THE APP - Main menu with your latest world turning in orbit - New planet: name, base and size - Surface editor with five brushes, live habitability readout and a regenerate button - Atmosphere and climate: density, temperature, humidity, weather, and what each does - Survey: composition, ice cover, the score explained - Collection of every world you keep, each one rendered live - Ten achievements, settings, animated star field you can switch off - Fully offline, no account, nothing to buy Build a paradise. Then build the opposite, just to see what happens.