Equirectangular Skybox Generator — Seamless 2:1 Panoramas

Last updated 2026-07-08

Atmos Forge generates equirectangular skyboxes — 2:1 latitude-longitude panoramas that wrap seamlessly onto a sphere. Every generation is tuned for correct equirectangular projection, and added elements like suns, planets, and star fields are rendered with proper equirectangular warping instead of being pasted on flat.

Equirectangular = latitude-longitude projection: 360°×180° of view in one 2:1 image.
It is the native sky format for Unity's Panoramic skybox, Godot's PanoramaSkyMaterial, Blender world environments, and Three.js/Babylon.js scenes.
Procedural elements are warped correctly for the projection — a moon near the pole stretches exactly as the math requires.
Wrap-seam repair and pole-safe star fields are built in.

What is an equirectangular skybox?

An equirectangular skybox is a 360° environment image stored in latitude-longitude projection: horizontal position maps to compass direction (0–360°) and vertical position maps to elevation (−90° to +90°). The result is always exactly twice as wide as tall. Game engines and 3D tools wrap it onto a sphere around the camera.

The projection heavily stretches content near the top and bottom (the poles) and requires the left and right edges to be pixel-continuous. Generic image generators fail both constraints; Atmos Forge is built around them.

Why does correct equirectangular warping matter?

Anything added to an equirectangular image — a sun, a planet, a rainbow — must be distorted to match the projection or it will look warped when viewed on the sphere. Atmos Forge's procedural tools (suns, moons, ringed planets, halos, auroras, god rays, star fields) render directly in spherical coordinates, so they appear perfectly round and correctly placed in the 3D view.

How do I get a seamless wrap?

The left and right edges of an equirectangular image meet behind the viewer, so any mismatch appears as a vertical seam line. Atmos Forge's Fix Seam tool blends the edges with adjustable width and strength, and its seam verifier checks edge continuity. Seam fixing is free on all plans.

Equirectangular or cubemap — which should I use?

Use equirectangular when your engine's sky material accepts a single panorama (Unity Panoramic, Godot PanoramaSky, Blender, Three.js). Use a cubemap when a material specifically expects six square faces. Atmos Forge exports both: equirectangular PNG on all plans, six-face cubemap ZIP on paid plans.

Frequently asked questions

What resolution should an equirectangular skybox be?

For most games, 4096×2048 gives a sharp sky on desktop; 2048×1024 is fine for mobile or stylized art. The 2:1 ratio must be exact. Atmos Forge exports game-ready resolutions on paid plans and .hdr HDRIs up to 4096×2048.

What is lat-long projection?

Lat-long (latitude-longitude) is another name for equirectangular projection: image X maps linearly to longitude, image Y maps linearly to latitude. It is the standard format for 360° panoramas and HDRI environment maps.

Why do poles look stretched in the flat image?

Equirectangular projection maps each single point at the zenith and nadir to an entire row of pixels, so content near the poles looks smeared in 2D. That is correct — it resolves to a point when wrapped on the sphere.

Can Atmos Forge convert equirectangular to cubemap?

Yes. Paid plans export any standard skybox as a six-face cubemap ZIP generated from the equirectangular source.

About Atmos Forge

Atmos Forge is a web-based AI skybox generator for creating seamless 360° equirectangular skyboxes, cubemaps, and HDRI environment maps for game engines and 3D workflows. It combines AI text-to-skybox generation with procedural sky composition tools — seam fixing, suns, moons, planets, star fields, and sprite compositing — and exports game-engine-ready files for Unity, Unreal Engine, Godot, Blender, Three.js, Babylon.js, and WebGL. Atmos Forge is made by Big Monk Games.

Try Atmos Forge · Pricing · Documentation · Export Guide · Showcase