Adding an Atmosphere

This guide walks through adding an atmosphere to your scene using Metaplanets Creator: Atmosphere — a standalone planetary sky system with volumetric clouds. It uses Hillaire 2020 scattering and supports multiple atmospheres per scene and multi-layer volumetric clouds; each atmosphere actor contributes independently to the sky composite and aerial perspective.

It's a standalone plugin, separate from Metaplanets Creator — available on Fab — so you can install just the atmosphere system. The steps below use the included example project.

1. Install the plugin

Copy the MetaplanetsAtmosphere folder from the download into your project's Plugins/ folder:

Restart the editor if needed, then open Edit → Plugins, go to Project → Rendering, and enable Metaplanets Atmosphere:

2. Place the atmosphere actor

Open the Place Actors menu (the green + in the main toolbar), hover the Metaplanets category, and drop a Metaplanets Atmosphere Actor into the scene — or just type meta in the search box at the top of the menu. Place it at the planet's center world position:

Each actor contains one AtmosphereComponent plus any number of MetaplanetsCloudLayer components (one per altitude band).

3. Set up the sun

The atmosphere is lit by a Directional Light. In the example, the light is placed at the same position as the atmosphere actor, aimed down at the surface:

Select the AtmosphereComponent in the Details panel. In the Sun section, link the light with Sun Light and tick Drive Sun Light so the sun in the shader tracks the light. Then tune Illuminance, Angular Radius, and Color to set the sky's character:

Illuminance

Since 2.0.1 the sky follows the directional light's own intensity and colour (Use Sun Light Intensity, on by default), like Unreal's Sky Atmosphere, and follows the camera exposure. Set the brightness on the light and the exposure on your camera, and sky, clouds and terrain stay in balance. The component's Illuminance is used only when Use Sun Light Intensity is off; then 10 to 150 are the recommended values — below 10 the sky reads dark and the scattering bands close up, and above 150 it blows out and loses the gradient.

The other sections — Atmosphere, Planet, Rayleigh, Mie, Ozone, Ground Fog, and Moon — shape the scattering. The Planet section is where you match the atmosphere to your planet's radius.

4. Add cloud layers

Add a MetaplanetsCloudLayer component to the actor (+ Add in the Details panel). Each layer occupies one altitude band:

Select the cloud layer and tune its Layer Params — Cloud Type, Altitude Inner/Outer Km, Coverage, Fluffiness, Density, and the SDF and noise-by-height parameters:

Here's the result — an overcast cloud deck lit by a high sun:

Every setting and ready-made cloud recipes are in Clouds: shapes & layers.

Fully customizable in C++ and shaders

The cloud system is fully customizable in C++ and shaders. Every cloud layer is driven by exposed parameters and render passes you can extend, so you're not limited to the preset cloud types — build your own.

Design the sky as a graph

Instead of setting Rayleigh, Mie, ozone, fog and cloud values by hand, you can build the whole sky as an Atmosphere Graph asset with a live preview, and set it on the AtmosphereComponent's Atmosphere Graph property.

Multiple atmospheres

Unreal's built-in sky atmosphere only supports one per scene. Metaplanets Creator: Atmosphere supports many — each Metaplanets Atmosphere Actor is an independent atmosphere, so a single space scene can show several planets, each with its own sky.

This example uses the same scattering settings on two instances to make the point:

The Outliner shows both instances — MetaplanetsAtmosphereActor and MetaplanetsAtmosphereActor2 — in the same level:

These atmospheres can also cast shadows, so one planet can obscure the sun from another — emulating an obstructing planet in a multi-planetary world.