Backwards compatibility: U3.5 asset bundle migration to U5.x

I have a project that is being brought back to support iOS 64bit.
It uses asset bundles build in Unity 3.5.
We'd like to use Unity 5.5. I'll take any version that supports 64bit.

The catch - we only have assetbundles and not the raw assets for some things.
And thus no way to rebuild the assetbundles.

We're using 2d Toolkit if that matters.

Is there some way to save assetbundles in the new format?
Is there some way to read in the raw assets and save them?
Any other suggestions?

0) The original unity project with these assets is lost
I have the project that loads the assetbundles.

1) I've found DisUnity that can extract some of the data.
https://github.com/ata4/disunity
It doesn't extract enough - no animationsClips, none of the GameObjects

2) I've tried dragging the item created in the scene into the project - it generates an object with empty elements. And none of the required assets

3) I've looked for scripts that will do something similar except in code.

4) I've considered rebuilding the scene by stepping through the objects in U3.5 but when I do that, I get the following popup error dialog:
- rebuilding index. scanning project folder
That hangs the Editor.



Here's a shortened list of the contents of one of the asset bundles.

PID | CID | Class name | Offset | Size | Object name
------------ | ---- | ------------------------ | ---------- | ---------- | -----------
1 | 142 | AssetBundle | 0x0 | 2096 |
2 | 21 | Material | 0x830 | 160 | background
3 | 21 | Material | 0x8d0 | 76 | atlas0 material
4 | 28 | Texture2D | 0x920 | 5592476 | atlas0
5 | 28 | Texture2D | 0x555ec0 | 699216 | back_tex
6 | 43 | Mesh | 0x600a10 | 8156 | room_wall_mesh
7 | 48 | Shader | 0x6029f0 | 1740 | BlendVertexColor
8 | 74 | AnimationClip | 0x6030c0 | 296 | background_scroll
9 | 83 | AudioClip | 0x6031e8 | 749576 | audio
10 | 115 | MonoScript | 0x6ba1f0 | 69 | tk2dSprite
11 | 115 | MonoScript | 0x6ba238 | 93 | tk2dSpriteCollectionData
12 | 1 | GameObject | 0x6ba298 | 63 | spriteCollection
21 | 1 | GameObject | 0x6ba4d8 | 59 | room
28 | 4 | Transform | 0x6ba6e0 | 60 |
29 | 4 | Transform | 0x6ba720 | 60 |
44 | 23 | MeshRenderer | 0x6bab50 | 64 |
45 | 23 | MeshRenderer | 0x6bab90 | 64 |
53 | 33 | MeshFilter | 0x6bad90 | 16 |
54 | 33 | MeshFilter | 0x6bada0 | 16 |
62 | 82 | AudioSource | 0x6bae20 | 164 |
63 | 108 | Light | 0x6baec8 | 104 |
64 | 108 | Light | 0x6baf30 | 104 |
65 | 108 | Light | 0x6baf98 | 104 |
66 | 111 | Animation | 0x6bb000 | 68 |

thanks.
Bob

 

The path I'm taking is dumping the object as a text file to disk as I'm creating it in Unity 3.5 after reading in from the assetbundle.
And then I'll recreate it in Unity 5.5 (even if manually, getting the data was the blocker)

My scene dumper is based on this:
http://wiki.unity3d.com/index.php?title=SceneDumper

Just writing out useful info like transform position, rotation (if not Q.identity), scale (if not Vector3.one)

Comparing two scenes, I would have never guessed the light rigs were different. Well, I did guess they might be. The dump showed me there were and what I need to do to recreate them.

The one thing I really wanted to recover was the animations. This looks like it should work.
http://answers.unity3d.com/questions/50596/possible-to-save-animations-created-from-script-as.html
And indeed it does, I am saving the "lost" animations.

Next, I'm going to look at using the AssetDatabase to save the primary game object so I don't have to recreate all the transform data in the tree.


+environment_one
Transform name: environment_one
Pos (0.0, 0.0, 0.0)
Rot (359.4, 180.0, 0.0)
AudioSource name: environment_one
Clip environment_one_audio
+background_static
Transform name: background_static
Pos (-12.0, -1.0, 15.7)
MeshFilter name: background_static
Mesh plane Instance
MeshRenderer name: background_static
tk2dSprite name: background_static
+LIGHT_RIG
Transform name: LIGHT_RIG
Pos (0.0, 12.0, 0.1)
Rot (359.4, 180.0, 0.0)
+back_light
Transform name: back_light
Pos (0.0, 0.0, 0.0)
Rot (55.0, 28.6, 203.2)
Light name: back_light
Color RGBA(0.872, 1.000, 0.459, 1.000) intensity 0.32
+key_light
Transform name: key_light
Pos (0.0, 0.0, 0.0)
Rot (27.2, 231.2, 34.0)
Light name: key_light
Color RGBA(0.846, 0.847, 0.578, 1.000) intensity 0.46
+back
Transform name: back
Pos (0.0, -3.4, 23.0)
Rot (359.4, 180.0, 0.0)
Scale (2.1, 2.1, 2.1)
MeshFilter name: back
Mesh room_wall_mesh
MeshRenderer name: back
Animation name: environment_one_back
Name environment_one_back
Saved as Assets/environment_one_back.anim