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:

Copy the MetaplanetsAtmosphere folder into the project's Plugins folder

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

Enable the Metaplanets Atmosphere plugin in the Plugins window

2. Place the atmosphere actor¶

Open the Place Actors menu (the green + in the main toolbar), search for meta, and drop a Metaplanets Atmosphere Actor into the scene. Place it at the planet's center world position:

Adding a Metaplanets Atmosphere Actor via Place Actors

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:

Directional light set up as the sun

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:

Sun settings in the AtmosphereComponent details panel

Illuminance

Illuminance sets how bright the sun reads in the sky. 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:

Adding a MetaplanetsCloudLayer component

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:

Cloud layer parameters

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

A rendered volumetric cloud layer

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.

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:

Two planets, each with its own atmosphere

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

Two atmosphere actors in the Outliner

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