Author whole planets by hand in HDRP: sculpt terrain, paint biomes, add ocean, sky and scattered props, then bake it for runtime.Planet Maker is an editor tool for building spherical worlds you design yourself. Instead of generating an endless universe from a seed, you shape one planet at a time, see the result in the Scene View as you work, and bake the finished world so builds load it instantly.Terrain is a non-destructive stack of layers on a planet asset. Start with fractal noise, sculpt hills and valleys by hand, drop heightmap stamps for craters and peaks, weather the result with thermal erosion, and flatten roads and river beds along splines. Every layer has a blend mode, opacity, and masks for height, slope, latitude and direction, so you can keep reordering and rebalancing without losing work. Undo works throughout, and sliders accept any value you type, so a crater a kilometre wide is never a range away.Biomes are placed by rules and then overridden by hand where you want something specific. Each biome carries its own tint, albedo, normal map, tiling and cliff angle, and is blended by height, slope, latitude and boundary noise. Paint over the rules with a brush, and the whole set is evaluated on the GPU and baked into the mesh, so it costs nothing at runtime.Around the terrain sits a complete sky: a shaded ocean with waves, foam, buoyancy and underwater fog, an atmosphere with adjustable scattering, terminator softness and stylising bands, a cloud shell, a procedural starfield with a nebula, and a visible sun with a corona that lights the world and drives a day cycle. Turn the water emissive and the same settings give you a lava world.Populate the surface by hand with the prop brush, or by rule with the scatter system, which grows props per biome and streams them around the camera from pools. Props stick to the terrain and re-snap when you reshape it. Splines make roads and ribbons, and points of interest give your code named places to find at runtime.The tool suits stylised space survival and exploration games, arcade flight, sci-fi sandboxes and small-planet platformers. Two playable demo scenes are included: a walking showcase with a first-person controller that handles walking, swimming and flying on any planet, and a three-planet solar system with a physics ship you can fly, land, and step out of to walk around. Gravity components come with it, so anything with a Rigidbody falls toward the nearest world.Documentation, sample biomes, stamps and props, and profiler markers on every system.Requires Unity 6 and the High Definition Render Pipeline. It does not support the Universal or Built-in pipelines. It is built for hand-authored worlds rather than infinite procedural generation, and the samples are single-player starting points rather than a finished game framework.Cube-sphere terrain with per-face quadtree LOD, meshes built by Burst jobs straight into MeshData and spread across framesNon-destructive layer stack: fractal noise (simple and ridged), hand sculpting, heightmap stamps, thermal erosion and spline paths, with per-layer blend mode, opacity and masksMasks by height, slope, latitude and angle from a planet-local axis, for tidally locked and polar worldsUp to eight biomes per planet, rule driven and hand paintable, evaluated on the GPU and baked into vertex data, with triplanar cliffsOcean shell with sea level, depth fade, foam, ripples, waves, emission for lava, buoyancy and an underwater fog passAtmosphere with adjustable scattering, planet shadow and terminator softness, sun glow, star hiding, density cap and orbit thinning, plus a cloud layerSpace sky with procedural stars, a two-colour nebula and dust band, driving ambient light, and a Planet Sun with a visible disc, corona and day cycleProp placement tools with palettes, weights, scale and yaw randomisation, slope alignment and spacing rules, all snapping to the surfaceRule-based scatter with per-biome density, noise clumping and view distance, streamed deterministically per cell from object poolsSplines that flatten terrain, generate ribbon meshes for roads and trails, and place prop lines, plus labelled points of interest with runtime lookupSpherical gravity components and a first-person sample controller that walks, swims and flies on any planetSolar system components: analytic circular orbits and spin with Kepler periods, summed gravity from every body, and a physics ship demo with landing and disembarkingRuntime bake writes the finished heightfield and biome map beside the asset so play mode and builds skip generation and compute shadersMesh colliders cooked on worker threads, with a chunk only replacing its parent once its collider is readyProfiler markers on every system and an on-screen performance overlay in the samplesFull C# source, two demo scenes, sample biomes, stamps and props, and written documentationUnity 6 with HDRP 17. HDRP onlyFor aid in technical and design purposes
