Altos

Overview

A complete sky system for Unity. Altos provides all the tools you need to craft a stunning sky: volumetric clouds, a procedural skybox, a day-night system, and more.

Replace your static skybox with Altos' infinitely customizable sky in 60 seconds without writing code or paying hundreds of dollars.

Easy to use. Beautiful results. No coding required.

• Fully dynamic and customizable sky.
• Fully customizable day-night cycle.
• Fully customizable volumetric clouds with high-quality temporal anti-aliasing, render scaling, and the ability to render in front of opaque geometry.
• Realistic sun, moon, and star rendering.
• Built-in atmospherics with horizon-blended depth fog.
  

Join hundreds of other game devs already using the best sky for Unity.

• "This asset does exactly what it says it does and does it beautifully. Easy to install and configure, it gives a very atmospheric feel to your scenes. Great work."
• "I absolutely love this asset! It helped my project so much and the clouds look amazing! Thank you so much for offering this Asset! :)"
• "By far the best sky I found at a good price and very well documented."
  

Powerful Features

Volumetric clouds

1. Drag-and-drop volumetric cloud setup.
2. Control the performance impact.
3. Profiled to <2ms at medium-quality settings.
4. Make it beautiful: Control the cloud density, cloudiness, lighting intensity, sun color influence, sky color influence, cloud layer height, and thickness, as well as base and detail noise scale and speed.

2D clouds

1. Set the speed for the cloud textures to pan through the skybox.
2. Configure the base color and shaded color for the clouds to easily fit your color palette.
3. Decide how much the sun influences the lighting of the clouds.
4. Change how much the clouds are affected by the color of the skies.
5. Easily transition from cloudy to clear skies with controllable cloud thresholds.
6. Modify the cloud and cloud shading sharpness to customize the look of your clouds - super soft and fluffy, or really crisp and stylized.
7. Uses custom UVs to ensure you can have clouds directly overhead without any UV “pulling” at the top of the skybox.

Time of Day Configuration

1. Configure any number of named "Times of Day" like Night, Dawn, Day, and Dusk with customized sky colors.
2. Control the size and color of the sun to fit your game’s atmosphere.
3. Easily skip to specific times in the day.
4. Control how long it takes to transition between different times of the day.
5. Set the overall day length with a controllable slider to determine how long one real-life second is in-game.

General

1. Built-in dithering to prevent banding on soft sky gradients.
2. User-friendly UI.‍‍‍

High Performance

1. Profiled to <2ms using medium-quality settings.
2. Control your performance impact using built-in performance controls and optional features.

Can I set the time of day via script?

Yes! Use the [.c]SetTime[.c] or [.c]SetDayAndTime[.c] public methods in the [.c]SkyDefinition[.c] scriptable object to set the day and time.

Can I fly through and above the volumetric clouds?

Yes. On your Cloud Definition, set the [.c]Rendering Mode[.c] to [.c]Clouds Render Over Opaque Objects[.c].

The clouds are too bright! What do I do?

• Open your Cloud Definition, click on Basic Configuration, and then look at your Lighting settings. You may need to adjust the Sun Color Mask, Ambient Exposure, or HG Strength.
• Now go to your Low Altitude Configuration and look at the Lighting settings there. You may need to adjust the Max Lighting Distance or the Multiple Scattering Octaves, Amp Gain, and Density Gain parameters to get the look you want.

Does this asset include 3D Textures?

Yes. We include 4 types of 3D noise at 4 quality levels for each type. These noise types include Perlin, Perlin-Worley, Worley, and Billow Noise.

Is Altos compatible with Forward and Deferred Render Paths?

Yes. Altos is compatible with both Forward & Deferred Render Paths.

Quick overview of the asset and how it works?

• Altos is a complete sky system composed of several individual modules. At a high level, Altos offers a Day-Night Cycle, Star Rendering, Sky Object (Sun, Moon, Planets) rendering, Atmosphere Rendering, Ambient Lighting, Low Altitude Cloud Rendering, and High Altitude Cloud Rendering system.
• These modules consist of a Sky Definition, Cloud Definition, Star Definition, and Atmosphere Definition. Altos also acts as the parent to one or more Sky Objects (Suns, Moons, Planets, etc.) each of which has its own configuration.
• Each module is configured via a [.c]Definition[.c], which is a Scriptable Object asset. As such, these Definitions are interchangeable and hot-swappable during editor and runtime.
• Altos is a completely standalone sky rendering process that fully displaces Unity's built-in process.

What's the sky rendering process?

• Black background to simulate dark space.
• Compute-shader based quad mesh stars, rendered with a custom star rendering shader. Blended additively over the space background
• Quad mesh sky objects, rendered with a custom sky object rendering shader - we simulate RGB wavelength atmospheric attenuation, RGB limb darkening, and more.
• Sky atmosphere, rendered with a custom sky atmosphere rendering shader - we use your keyframes together with the time of day and the sky object positions to influence the sky color.
• Low altitude and high altitude clouds rendered as a single pass - these can be depth tested or rendered to the skybox.
• Cloud shadow pass, rendered to a texture and then to the screen.

Can I fly into space?

No. Altos is designed for terrestrial surface- and near-surface based use cases.

Is Altos compatible with URP decals?

Yes. Altos is fully compatible with URP decal rendering.

When I enable Altos, I receive console warnings for Resource ID is out of range. What do I do?

Altos may have been incorrectly set up when importing into your project. Try re-importing Altos or importing Altos to a clean project.

Is Altos designed for VR?

No, Altos has not been designed for VR and may not work on some or all VR devices.

Does Altos support multiple directional shadows?

Universal Render Pipeline currently does not support multiple directional shadow casters. We want to write a full extension to Unity URP to offer support for multiple directional shadow casters to enable this use case, but for now we are stuck with the URP single directional light shadow caster constraint.

When I make the Sky Director a prefab, I get an error and/or my sky objects don't render correctly. What do I do?

The SkyObjects list may need to be refreshed. Try entering Play mode, then exiting Play mode. Validate if the issue is resolved.

Can I disable Altos for specific cameras?

Yes. This can be useful for Overlay, UI, or Effects-related cameras. To disable Altos for a specific camera, simply add the [.c]DisableAltosRendering[.c] component to that camera.

Does Altos include any star textures?

Yes. Altos includes 9 star textures that you can use to customize the stars in your game. You can also author your own star textures.