docs.unity3d.com
    Show / Hide Table of Contents

    Ambient Occlusion

    The Ambient Occlusion effect calculates points in your scene that are exposed to ambient lighting. It then darkens areas that are hidden from the ambient light, such as creases, holes, and spaces between objects which are close together.

    You can achieve the Ambient Occlusion effect in two ways: in real-time as a full-screen post-processing effect, or as a baked lighting effect (see Baked Ambient Occlusion). The real-time Ambient Occlusion effect can be resource-intensive, which makes it better for desktop or console platforms. Its impact on processing time depends on screen resolution and effects properties.

    The Ambient Occlusion effect in this package has two modes:

    • Scalable Ambient Obscurance
    • Multi-scale Volumetric Occlusion

    Scalable Ambient Obscurance

    This is a standard implementation of ambient obscurance that works on older platforms. If you need to target a compute-enabled platform, use the Multi-scale Volumetric Occlusion mode instead.

    Performance

    The Scalable Ambient Obscurance mode can be resource-intensive, especially when viewed very close to the Camera. To improve performance, use a low Radius setting, to sample pixels that are close and in clip space to the source pixel. This makes caching more efficient. Using a higher Radius setting generates samples further away from the source pixel and won’t benefit from caching, which slows down the effect.

    Because of the Camera’s perspective, objects near the front plane use larger radiuses than those far away, so computing the ambient occlusion pass for an object close to the camera will be slower than for an object further away that only occupies a few pixels on screen.

    Dropping the Quality setting down will improve performance too.

    Scalable Ambient Obsurance should not be used on mobile platforms or consoles as the Multi-scale Volumetric Occlusion mode is faster and provides better graphics for these platforms.

    Requirements

    • Depth & Normals textures
    • Shader model 3

    Properties

    Property Function
    Intensity Adjust the degree of darkness Ambient Occlusion produces.
    Radius Set the radius of sample points, which controls the extent of darkened areas.
    Quality Define the number of sample points, which affects quality and performance.
    Color Set the tint color of the ambient occlusion.
    Ambient Only Enable this checkbox to make the Ambient Occlusion effect only affect ambient lighting. This option is only available with the Deferred rendering path and HDR rendering.

    Multi-scale Volumetric Occlusion

    This mode is optimized for consoles and desktop platforms. It has better graphics and runs faster than Scalable Ambient Obscurance on these platforms but requires compute shader support.

    Requirements

    • Compute shader support
    • Shader model 4.5

    Properties

    Property Function
    Intensity Adjust the degree of darkness Ambient Occlusion produces.
    Thickness Modifier Modify the thickness of occluders. This increases dark areas but can introduce dark halos around objects.
    Color Set the tint color of the ambient occlusion.
    Ambient Only Enable this checkbox to make the Ambient Occlusion effect only affect ambient lighting. This option is only available with the Deferred rendering path and HDR rendering.
    Back to top
    Terms of use
    Copyright © 2023 Unity Technologies — Terms of use
    • Legal
    • Privacy Policy
    • Cookies
    • Do Not Sell or Share My Personal Information
    • Your Privacy Choices (Cookie Settings)
    "Unity", Unity logos, and other Unity trademarks are trademarks or registered trademarks of Unity Technologies or its affiliates in the U.S. and elsewhere (more info here). Other names or brands are trademarks of their respective owners.
    Generated by DocFX on 18 October 2023