BuildAssetBundle results in System.InvalidCastException

Question

My code is posted below. You pass it a directory, and it should package all the assets in the directory into an AssetBundle. Instead, it crashes with an "System.InvalidCastException: Cannot cast from source type to destination type." error on the "BuildPipeline.BuildAssetBundle" line.

If I call "BuildAssetBundle(objs[0], null", everyt$$anonymous$$ng works great. If I call "BuildAssetBundle(objs[any_number_up_to_length_of_array], null", everyt$$anonymous$$ng works great. I can't figure out why Unity doesn't like my Object[] array, and why it won't let me build multiple assets into a bundle instead of just one at a time...

//Directory of assets to package into bundle var ab : String = "Assets/Path/To/Assets/To/Package/";

//Determine title for t$$anonymous$$s bundle
var offset : int = ab.Substring(0, ab.length-2).LastIndexOf("/") + 1;
var title : String = ab.Substring(offset, ab.length - offset - 1) + ".unity3d";

//Iterate through each file to be built in t$$anonymous$$s bundle
var objArr : Array = new Array();
var files : String[] = System.IO.Directory.GetFiles(ab, "*", System.IO.SearchOption.AllDirectories);
for(var file : String in files) objArr.Add(AssetDatabase.LoadMainAssetAtPath(file));

//Build Bundle!
var objs : Object[] = objArr.ToBuiltin(Object);
BuildPipeline.BuildAssetBundle(null, objs, title);

Answer 1

Best Answer

Answer by Aubrey-Falconer · Dec 10, 2009 at 07:25 PM

NCarter just solved t$$anonymous$$s for me on the #Unity3D chat!

"Object" by default references System.Object and not UnityEngine.Object.

Explicitly referencing UnityEngine.Object resolved the issue.

T$$anonymous$$s is either a bug or a very strange design decision in Unity's JS implementation...

Add comment · Share

Answer 2

Answer by Aubrey-Falconer · Dec 10, 2009 at 05:43 PM

Here's some code simplified as much as it could possibly be - I just don't understand how it can fail to run properly.

Debug.Log(file); //Assets/W$$anonymous$$rlds/MarsAssets/Textures/Dirt.png Debug.Log(title); //Textures.unity3d

var objs : Object[] = new Object[1];
objs[0] = AssetDatabase.LoadMainAssetAtPath(file);
BuildPipeline.BuildAssetBundle(null, objs, title);  //System.InvalidCastException: Cannot cast from source type to destination type.

Add comment · Share

BuildAssetBundle results in System.InvalidCastException

2 Replies

Your answer

Welcome to Unity Answers

Follow this Question

Related Questions