HDRI to cubemap.
In the browser.

THE MATH, IN ONE PARAGRAPH

A 360° equirectangular panorama is a sphere unwrapped into a rectangle. A cubemap is the same scene re-projected onto the six faces of a cube around the viewer. The conversion samples each face by casting a 90° FOV pinhole camera in the six axis directions and reading where each ray meets the sphere.

SUPPORTED FORMATS

.exr

OpenEXR, half- or full-float. HDR range preserved end-to-end when you pick an HDR output encoder.

.hdr / .hdri

Radiance RGBE. Same handling as EXR.

.png

8-bit, fine if your source is already tone-mapped.

.jpg / .jpeg

8-bit, lossy. Expect compression artifacts at face edges.

COORDINATES

Right-handed, +Y up. 90° FOV pinhole per face, sampled at pixel centers. Face-up aligned to the horizontal-cross convention used by Blender, Unity, and Unreal.

GUIDES

Cubemap or equirectangular?

Most engines accept an equirectangular HDRI directly. A few need six cubemap faces. A per-engine breakdown of which input each engine wants.

HDRI to Source engine skybox

Turn an equirectangular HDRI into a Source engine skybox. The converter builds VTF face textures and VMT materials for materials/skybox/ in LDR and HDR.

How to use an HDRI in Blender

Light a Blender scene with an HDRI through the World shader: setup, how to rotate the HDRI, Eevee notes, and exporting an HDR for cubemap engines.

HDRI to Unity skybox

Make a Unity skybox from an equirectangular HDRI: the Skybox/Panoramic material, the cube texture shape, and the legacy six-sided shader.

HDRI in Unreal Engine

Light an Unreal Engine level with an HDRI: the HDRI Backdrop plugin, a Sky Light with a specified cubemap, and the import settings that matter.

HDRI to Godot skybox

Use an HDRI in Godot 4: set up the sky with WorldEnvironment and PanoramaSkyMaterial, light the scene from it, and rotate it without nodes.

All guides →

QUESTIONS

Does my HDRI get uploaded anywhere?

No. The converter runs in your browser on your GPU via WebGL. The file never leaves your machine. The page is static, so there is no server to upload to.

Will my HDR data survive the export?

Yes, if you pick an HDR encoder. The viewer's EXPORT panel offers PNG, JPG, and 8-bit TGA (clamped to LDR), 16-bit TGA, PFM at 32-bit float, EXR at half- or full-float, and Radiance HDR. The converter samples the panorama in HDR at every step. The export format decides whether it keeps or clamps the floats.

Which coordinate convention does it use?

Right-handed, +Y up, 90° FOV pinhole per face, sampled at pixel centers. Right=+X, Left=-X, Up=+Y, Down=-Y, Front=+Z, Back=-Z. This is the convention Blender, Unity, and Unreal share.

Will it work with a 16K panorama?

It will try. Most browsers cap a single texture at ~16384 px on the long edge, and most run out of memory before that. A 4K panorama gives the best balance of detail and reliability. An 8K panorama works on a 16 GB machine. A 16K panorama works on some machines and fails on others.

Does it output Source engine skyboxes?

Yes. The Source Skybox bundle in the sidebar EXPORT section produces six VTF face textures and the matching VMT materials, named in the Source convention. Copy them into materials/skybox/ in your mod or game folder. If you need a finished sky, Source Skyboxes offers finished Source engine skyboxes as free downloads. We maintain that site as well.

Can I use the output commercially?

Yes. The converter asserts no rights over your files. Your HDRI keeps the license its source attaches. This page adds no license terms.