World creation

Skies

Choose the sky of your world: a colour, stars, a 360° picture, an HDR or EXR panorama, or the dynamic sky with weather and day and night. Optionally, shiny and metal surfaces reflect it.

Choosing A Sky

In the Scene Editor, open Windows → Scene Settings and pick a Sky. It changes as you edit and is saved with the world (File → Save). Visitors see the same sky on computers, phones and in VR.

Plain colour

One background colour. The lightest and fastest.

Star field

Stars all around, with their count, size, colours, twinkle and spin.

360° picture

A normal picture (PNG, JPG or WebP) wrapped around the world, added with Inventory → Import… and chosen in Scene Settings. Quick and cheap, but it is only 8-bit: the sun and bright clouds clip to white, and most 360° pictures look smeared or pinched at the very top and bottom of the sky. Uses the Texture upload limit.

Dynamic sky

A moving sky with clouds, weather and day and night (see Scene Editor → Dynamic Sky And Weather).

HDR sky (.hdr)

A high dynamic range panorama in the Radiance .hdr format. Real brightness: a bright sun, soft clouds and dark shadows all in one picture, smooth all the way up and down. The best choice for a realistic sky.

EXR sky (.exr)

The same in the OpenEXR .exr format, which is what most free sky and HDRI libraries offer for download. EXRs are bigger (often 30-75 MB).

HDR And EXR Skies

Download a sky panorama as .hdr or .exr. It must be equirectangular (2:1, e.g. 4096 × 2048 or 8192 × 4096), the usual format of HDRI libraries.
Add it to your inventory: Inventory → Import… (like any other asset). It becomes an HDR sky or EXR sky item that you can also sell, give away or buy in the Store like other items.
In Scene Settings set Sky to HDR sky or EXR sky and choose it, or simply double-click it in the inventory to make it the scene's sky.
Adjust Exposure until it looks right (1 = as the file is), and Rotation to turn the sky (e.g. to put the sun where your Directional Light comes from).

File size

Each format has its own upload limit, set by the platform owner (by default 50 MB for an HDR and 75 MB for an EXR; Pro members more). See Quotas for the limits of this platform.

Sharpness

Computers show the sky at up to 4096 pixels wide, phones and VR headsets at up to 2048 (they have far less graphics memory). A bigger file still works: it is made smaller on that device. An 8K file only costs more download time.

Loading

The sky is read in the background, so the world does not freeze while a big EXR loads. Until it arrives, the background colour shows.

Supported files

.hdr (Radiance RGBE) and .exr (OpenEXR, the usual compressions). Multi-part and deep EXRs are not supported.

Reflections

Turn on Reflections in Scene Settings to make shiny and metal surfaces (materials with metalness, or low roughness) reflect the sky. It works with 360° pictures, HDR and EXR skies and the dynamic sky, and is off by default.

Only the sky is reflected, not the world's own objects, terrain or trees.
It is one small, pre-blurred reflection picture made when the sky loads, so it stays light on phones and in VR. A dynamic sky refreshes it every few seconds (time of day, clouds) and during lightning.
HDR and EXR skies give the best reflections: their Exposure also sets how bright the reflections are.
Turning it on or off makes the materials of the world update once, which can take a moment in big worlds.

Reflection Probes

To make shiny things reflect the world around them too (terrain, trees, buildings, not only the sky), add a Reflection Probe from System Objects and place it where the shiny things are, e.g. in the middle of a car showroom. It only works while Reflections is on in Scene Settings.

Radius

Shiny and metal parts (metalness 0.2 or more, or roughness 0.5 or less) whose centre is this close use the probe's reflection; with several probes, the nearest wins. Everything further away keeps the sky's reflection.

Resolution

64, 128 (default) or 256 on computers. Phones and VR headsets always use 64.

Refresh

Once (default): taken when the world has loaded, and again when the probe moves or the sky changes. Choose every 5, 15 or 60 s only for moving things nearby or a dynamic sky (phones and VR refresh at most every 30 s).

Capture Now

Takes it again at once in the editor, after you moved things around it.

Performance

Players are not in the reflection. One probe is taken per frame, so many probes never cause one big hitch. Phones and VR use only the 4 probes nearest to the player. Each probe's shiny parts are drawn on their own, so use probes where they matter rather than all over the world.