Unity Asset Bundles - Which Files Do I Deploy?

Question

I have created some asset bundles from my Unity assets using the directions given in the Unity documentation section on AssetBundle Workflow. After running the "Build AssetBundles" command, each asset bundle results in four files: myasset, myasset.meta, myasset.manifest, myasset.manifest.meta.

Now I am ready to deploy these bundles to a web server and implement downloading/caching in my Unity project. I have found numerous examples such as this that show the download URL to be a single file with a .unity3d extension. This is leading me to conclude that I am missing a step - I assume that all four of my files will be required by the app and that I have to do something to combine them into a .unity3d file first.

What file(s) do I need to deploy? Are there any additional steps that I need to take before my file(s) are ready to upload? Thanks in advance for any advice!

Answer 1

Just myasset will suffice.

Sometimes people optionally add .unity3d as a filename extension to their Asset Bundles. It is just a community convention, and is completely optional. Source (copied below)

Vincent-Zhang

Unity Technologies

Just a reminder, we don't have an official file extension ".unity3d" for asset bundle, it's not mandatory. You can use whatever file extension as you want, or without file extension.

But usually people use ".unity3d" as the file extension just because we used it in the official sample code at first time...

Answer 2

Unity creates the .meta files for all assets- you don't have to worry about those. In short, your myasset file is enough. I do not add file extensions to mine. Do note that if you use the strategy shown in the example that you shared that the client will re-download the bundle from the server every time. You need to additionally provide a version number if you want to take advantage of caching. You can see this in some of the method overloads here, the ones that have a Hash128 or uint "version" parameter. Caching is great because you can use the bundle that is already saved on the device next time instead of downloading from the server when no changes have occurred. The version/hash number you provide essentially gets mapped to the file name. Whenever a matching version is found, the file on disk is used. Update the version number to something else when the content changes to force the client to download anew.

You may want to reference the .manifest file for the CRC value listed there. You may have noticed a crc parameter in the link I shared as well. This can be used to ensure data integrity during transmission of the bundle data. You can make sure the downloaded content's CRC matches that of the bundle when you created it.