Omits type information from the AssetBundle.
This flag is useful for AssetBundles that are included within Player builds and are rebuilt for every new Player release.
However, before using this flag, it is critical to fully understand the compatibility and redistribution implications of removing Type Trees.
By default (when this flag is not specified), each SerializedFile inside an AssetBundle contains the Type Tree information for all types used in that file.
Type Trees enable Unity to:
When this flag is specified only the hash of each Type Tree is recorded in the SerializedFile headers, not the entire Type Tree definition.
Example:
Suppose an AssetBundle includes instances of a MonoBehaviour-derived class with two fields: a string `A` followed by an integer `B`.
The Type Tree records the order, types and names of the fields so that the binary presentation of each serialized object of that type can be interpreted properly.
Then suppose the class definition changes to include a float `C` first, followed by integer `B` and string `A`.
The Type Tree inside the AssetBundle ensures that new builds of the Player can still load it, recovering the values of the `A` and `B` fields even though they do not match the current definition
of that class.
Advantages to using DisableWriteTypeTree:
Omitting Type Trees reduces AssetBundle size, which can be significant for projects with many small AssetBundles
or complex scripting types containing numerous fields or deeply nested structs.
Therefore this flag can be a useful optimization in cases where you know that you will always
rebuild and redistribute all AssetBundles any time that you rebuild your player.
Important Considerations:
AssetBundles built without Type Trees will have strict compatibility requirements:
binary2text and UnityDataTools cannot view the serialized data.
Platform Limitations
For some platforms (e.g. BuildTarget.WebGL), Type Trees are mandatory. Unity will reject attempts to build AssetBundles with this flag for such targets.