BuildPipeline.BuildAssetBundles

Parameters

Returns

AssetBundleManifest The manifest summarizing all AssetBundles generated by the build.

Description

Build AssetBundles.

This signature of BuildAssetBundles is recommended and exposes the most functionality. The other signatures, documented below, are retained for backward compatibility and convenience.

During the AssetBundle build process, classes that implement IProcessSceneWithReport will be called as Scenes are processed. Similarly the way Shaders are built can be influenced by implementing IPreprocessShaders or IPreprocessComputeShaders.

This function returns an AssetBundleManifest instance that describes the bundles produced. If the build fails then the function returns null or throws an exception. You can find details about what went wrong in the exception message or in errors logged to the console. For example, if you pass an invalid or non-existent path as the outputPath parameter, the function throws an ArgumentException to indicate that the supplied argument was invalid.

Additional resources: AssetBundles, EditorBuildSettings.UseParallelAssetBundleBuilding

using System.Collections.Generic;
using System.IO;
using System.Linq;
using UnityEngine;
using UnityEditor;

public class BuildAssetBundlesExample
{
    [MenuItem("Example/Build AssetBundles")]
    static void BuildBundles()
    {
        List<AssetBundleBuild> assetBundleDefinitionList = new();

        // Define two asset bundles, populated based on file system structure

        // The first bundle is all the scene files in the Scenes directory (non-recursive)
        {
            AssetBundleBuild ab = new();
            ab.assetBundleName = "Scenes";
            ab.assetNames = Directory.EnumerateFiles("Assets/" + ab.assetBundleName, "*.unity", SearchOption.TopDirectoryOnly).ToArray();
            assetBundleDefinitionList.Add(ab);
        }

        // The second bundle is all the asset files found recursively in the Meshes directory
        {
            AssetBundleBuild ab = new();
            ab.assetBundleName = "Meshes";
            ab.assetNames = RecursiveGetAllAssetsInDirectory("Assets/" + ab.assetBundleName).ToArray();
            assetBundleDefinitionList.Add(ab);
        }

        string outputPath = "MyBuild";  // Subfolder of the current project

        if (!Directory.Exists(outputPath))
            Directory.CreateDirectory(outputPath);

        // Assemble all the input needed to perform the build in this structure.
        // The project's current build settings will be used because target and subtarget fields are not filled in
        BuildAssetBundlesParameters buildInput = new()
        {
            outputPath = outputPath,
            options = BuildAssetBundleOptions.AssetBundleStripUnityVersion,
            bundleDefinitions = assetBundleDefinitionList.ToArray()
        };
        AssetBundleManifest manifest = BuildPipeline.BuildAssetBundles(buildInput);

        // Look at the results
        if (manifest != null)
        {
            foreach (var bundleName in manifest.GetAllAssetBundles())
            {
                string projectRelativePath = buildInput.outputPath + "/" + bundleName;
                Debug.Log($"Size of AssetBundle {projectRelativePath} is {new FileInfo(projectRelativePath).Length}");
            }
        }
        else
        {
            Debug.Log("Build failed, see Console and Editor log for details");
        }
    }

    static List<string> RecursiveGetAllAssetsInDirectory(string path)
    {
        List<string> assets = new();
        foreach (var f in Directory.EnumerateFiles(path, "*", SearchOption.AllDirectories))
            if (Path.GetExtension(f) != ".meta" &&
                Path.GetExtension(f) != ".cs" &&  // Scripts are not supported in AssetBundles
                Path.GetExtension(f) != ".unity") // Scenes cannot be mixed with other file types in a bundle
                assets.Add(f);

        return assets;
    }
}

In addition to the AssetBundle files, the build will produce several other files:

* The AssetBundleManifest is stored in a small AssetBundle that has the same name as the output folder, for example "MyBundleFolder". This is the same object that is returned from the BuildAssetBundles call, and the serialized form can be useful at runtime, for example to determine the expected hashes of the other AssetBundles.

* The main ".manifest" file, which is a text format file. It has the same name as the output folder, but using ".manifest" as its extension (for example: "MyBundleFolder.manifest"). Assign the path to this manifest file to BuildPlayerOptions.assetBundleManifestPath before calling BuildPipeline.BuildPlayer to make sure that any types appearing in the AssetBundles are not stripped from the build. (See Managed code stripping for more information about code stripping.)

* There is also a separate ".manifest" file written for each AssetBundle, based on the name of the AssetBundle.

* Finally, the BuildReport for the build is written to "Library/LastBuild.buildreport".

using System.IO;
using UnityEngine;
using UnityEditor;

public class BuildAssetBundlesOutputFileExample
{
    [MenuItem("Example/AssetBundle Output File Example")]
    static void BuildAndPrintOutputFiles()
    {
        var bundleDefinitions = new AssetBundleBuild[]
        {
            new AssetBundleBuild
            {
                assetBundleName = "mybundle",
                assetNames = new string[] { "Assets/Scenes/Scene1.unity" }
            }
        };

        string buildOutputDirectory = "build";
        Directory.CreateDirectory(buildOutputDirectory);

        BuildAssetBundlesParameters buildInput = new()
        {
            outputPath = buildOutputDirectory,
            bundleDefinitions = bundleDefinitions
        };

        AssetBundleManifest manifest = BuildPipeline.BuildAssetBundles(buildInput);
        if (manifest != null)
        {
            var outputFiles = Directory.EnumerateFiles(buildOutputDirectory, "*", SearchOption.TopDirectoryOnly);

            //Expected output (on Windows):
            //  Output of the build:
            //      build\build
            //      build\build.manifest
            //      build\mybundle
            //      build\mybundle.manifest
            Debug.Log("Output of the build:\n\t" + string.Join("\n\t", outputFiles));
        }
    }
}

Parameters

Returns

AssetBundleManifest The manifest listing all AssetBundles included in this build.

Description

Build all AssetBundles.

Use this function to build AssetBundles based on the AssetBundle and Label settings you have configured in the Editor. (See the Manual page about AssetBundles workflow for further details.)

Set outputPath to the folder within your project folder where you want to save the built bundles (for example: "Assets/MyBundleFolder"). The folder is not created automatically and the function simply fails if it doesn't already exist.

Use the optional assetBundleOptions argument to specify bundle build options.

The targetPlatform argument selects which deployment target (Windows Standalone, Android, iOS, and so on) to build the bundles for. An AssetBundle is only compatible with the specific platform that it was built for, so you must produce different builds of a given bundle to use the assets on different platforms.

For new code, the signature of BuildAssetBundles accepting a BuildAssetBundlesParameters structure is recommended instead of this one. To match the behaviour of this signature leave the BuildAssetBundlesParameters.bundleDefinitions field unassigned so that the Editor's AssetBundle assignments are used.

Additional resources: EditorUserBuildSettings.activeBuildTarget, AssetDatabase.GetAssetPathsFromAssetBundle, AssetDatabase.GetImplicitAssetBundleName, AssetImporter.assetBundleName, AssetBundle

// Create an AssetBundle for Windows.
using UnityEngine;
using UnityEditor;
using System.IO;

public class BuildAssetBundlesExample
{
    [MenuItem("Example/Build Asset Bundles")]
    static void BuildABs()
    {
        // Put the bundles in a folder called "ABs" within the Assets folder.
        string outputPath = "Assets/ABs";
        Directory.CreateDirectory(outputPath);
        BuildPipeline.BuildAssetBundles(outputPath, BuildAssetBundleOptions.None, BuildTarget.StandaloneWindows64);
    }
}

Parameters

Returns

AssetBundleManifest The manifest listing all AssetBundles included in this build.

Description

Build AssetBundles from a building map.

This signature of BuildAssetBundles lets you specify the names and contents of the bundles programmatically, using a "build map" rather than with the details set in the editor. The map is simply an array of AssetBundleBuild objects, each of which contains a bundle name and a list of the names of asset files to be added to the named bundle.

For new code, the signature of BuildAssetBundles accepting a BuildAssetBundlesParameters structure is recommended instead of this one. When using that signature the build map is assigned to BuildAssetBundlesParameters.bundleDefinitions.

using UnityEngine;
using UnityEditor;
using System.IO;

public class BuildAssetBundlesBuildMapExample
{
    [MenuItem("Example/Build AssetBundles with Build Map")]
    static void BuildMapABs()
    {
        // Create the array of bundle build details.
        AssetBundleBuild[] bundleDefinitions = new AssetBundleBuild[2];

        bundleDefinitions[0].assetBundleName = "enemybundle";
        bundleDefinitions[0].assetNames = new string[]
        {
            "Assets/Textures/char_enemy_alienShip.jpg",
            "Assets/Textures/char_enemy_alienShip-damaged.jpg"
        };

        bundleDefinitions[1].assetBundleName = "herobundle";
        bundleDefinitions[1].assetNames = new string[]
        {
            "Assets/char_hero_beanMan.prefab"
        };

        string outputPath = "Assets/ABs";
        Directory.CreateDirectory(outputPath);
        BuildPipeline.BuildAssetBundles(outputPath, bundleDefinitions, BuildAssetBundleOptions.None, BuildTarget.StandaloneWindows64);
    }
}