HDRI skyboxes for Unity

Set up an HDRI skybox in Unity (Built-in and URP)

1. Drop the .exr or .hdr file into the Assets folder.
2. Select it and, in the Inspector, set Texture Shape to Cube, Mapping to Latitude-Longitude Layout (Cylindrical), Convolution Type to None and Max Size to 8192 or 16384. Click Apply.
3. Create a material (Assets > Create > Material), set its shader to Skybox/Cubemap and assign the cubemap.
4. Open Window > Rendering > Lighting, Environment tab, and set Skybox Material to the new material. Environment Lighting Source: Skybox, Environment Reflections Source: Skybox.
5. Use the material's Rotation slider to line the sun up with your scene and Exposure to balance brightness.
6. Set the scene's Directional Light to match the sun direction, or delete it for a pure image-based setup with baked or real-time GI.

Try before you buy: the free HDR skyboxes need no account and carry the same licence as the paid files, so you can check the setup above with a real file before buying.

The Skybox/Panoramic shader also works with the panorama as a plain 2D texture (Texture Shape 2D, Mapping Latitude-Longitude), which skips the cubemap conversion but renders a little slower.

HDRP: HDRI Sky

1. Import the file as a cubemap as above.
2. Add a Volume to the scene (GameObject > Volume > Global Volume) and a Visual Environment override with Sky Type set to HDRI Sky.
3. Add an HDRI Sky override, assign the cubemap, set Intensity Mode to Exposure (or Lux for a measured sun) and Rotation to align the sun.
4. HDRP lights the scene from the sky directly; add a Directional Light with Sun Disk only if you need its shadow controls.

Unity skybox packs on Fab

If you would rather skip the import settings, two HDRI Hub skybox packs are on Fab as Unity packages with the cubemap presets already applied, tested in Built-in, URP and HDRP:

• Above the Clouds Pack: 15 aerial 8K HDRI skyboxes, unclipped sun for flight, drone and vehicle scenes.
• Space Sky Pack: 8 outer-space 12K skyboxes with stars, nebula, galaxy and planet.

The same skies are below as single downloads in more resolutions, including 16K domes and pre-split 6-face cubemaps for the space skies.

Which resolution

A cubemap is six faces; Unity makes each face roughly a quarter of the panorama width, so an 8192 x 4096 file gives 2048 px faces and a 16384 x 8192 file gives 4096 px faces. For lighting and reflections, 4096 x 2048 is enough. For a visible sky in a desktop or VR project, use 8192 x 4096 or larger with Max Size raised to match; for mobile, stay at 4096 x 2048 and compress.

Sun and shadows

An unclipped sun in the HDRI gives correct specular highlights and a convincing sky, but Unity's real-time shadows still come from a Directional Light. Rotate the light to the sun's position in the skybox (the Rotation value of the skybox material helps you line it up), then set its intensity and colour to match the HDRI's sun. HDRI Hub has 52 unclipped outdoor skies for this.

Frequently asked questions

Why is my skybox blurry?

Max Size in the import settings was left at 2048. Raise it to 8192 or 16384 and Apply.

.exr or .hdr?

Unity reads both at full float precision. HDRI Hub delivers .exr for skies from HDR 142 onwards and .hdr for earlier skies. Details in .hdr or .exr.

Seams in the cubemap?

Set Convolution Type to None for the skybox cubemap and make sure Mapping is Latitude-Longitude, not Auto. For a blurred reflection probe, use a second import with Convolution Type Specular.

Does the Fab skybox pack work with my Unity version?

The packs are built for Unity 2019.4 and later and tested in Built-in, URP and HDRP; the .unitypackage imports through Assets > Import Package.

More background: which HDRI resolution you need and HDRI skies for aviation renders.