Hello!

In order to import a json exported with Spine v3.8 into v3.7 you will need to use the JsonRollback tool.

1. Export a json with "Nonessential data" checked in the export settings, otherwise the mesh information might be lost.

2. Download Skeleton Viewer from this page: Skeleton Viewer

3. Make sure to have java installed and up to date: http://www.java.com/

4. Copy skeletonViewer-beta.jar in the folder where you saved the json exports

5. Launch the command line, then type this command, structured as follows:

   java -cp "skeletonViewer.jar" com.esotericsoftware.spine.JsonRollback "the-file-to-convert.json"  "3.7" "the-file-destination.json"  

   For example, in my case I launched this command:

   java -cp "C:\Users\Admin\Desktop\json\skeletonViewer.jar" com.esotericsoftware.spine.JsonRollback "C:\Users\ Admin\Desktop\json\oldfile.json"  "3.7" "C:\Users\Admin\Desktop\json\3.7\newfile.json"

(you can also save this text in a file and rename it with a .bat extension, then double click it to execute it)

6. downgrade Spine to v3.7 and import the generated json

The command line is located in different places depending on your operating system: https://arian-celina.com/windows-cmd-macos-terminal-navigation/

Hi! Not sure what I am doing wrong, but I am getting these errors.

PS C:\Users\kate> java -cp "C:\Users\kate\Documents\TESTESTESTEST\skeletonViewer.jar" com.esotericsoftware.spine.JsonRollback "PiggyButton.json" "3.7" "PiggyButton2.json"
Exception in thread "main" com.badlogic.gdx.utils.SerializationException: Error reading file: PiggyButton.json
at com.badlogic.gdx.utils.Json.fromJson(Json.java:758)
at com.esotericsoftware.spine.JsonRollback.main(JsonRollback.java:64)
Caused by: com.badlogic.gdx.utils.SerializationException: Error parsing file: PiggyButton.json
at com.badlogic.gdx.utils.JsonReader.parse(JsonReader.java:78)
at com.badlogic.gdx.utils.Json.fromJson(Json.java:756)
... 1 more
Caused by: com.badlogic.gdx.utils.GdxRuntimeException: Error reading file: PiggyButton.json (Absolute)
at com.badlogic.gdx.files.FileHandle.read(FileHandle.java:150)
at com.badlogic.gdx.files.FileHandle.reader(FileHandle.java:169)
at com.badlogic.gdx.utils.JsonReader.parse(JsonReader.java:76)
... 2 more
Caused by: java.io.FileNotFoundException: PiggyButton.json (The system cannot find the file specified)
at java.io.FileInputStream.open0(Native Method)
at java.io.FileInputStream.open(Unknown Source)
at java.io.FileInputStream.<init>(Unknown Source)
at com.badlogic.gdx.files.FileHandle.read(FileHandle.java:146)
... 4 more

Any idea how to fix this? Cheers

Hi! It looks like the JsonRollback can't read the json. Did you export it from v3.8 with "Nonessential data" checked?
Did you use the latest version of the jar to launch it?

That is correct. Exported with 3.8.72 and using Skeleton Viewer, v3.8.61. Attached is a picture of what my export settings look like...

You don't need to check pretty print in this case. Did you get any warning on export? did you use features not present in older versions of Spine, such as skin bones?

There are other skeletons in the project that use skin placholders, but not on the specific skeleton I am using the json of... No warnings on export.

You need to run this command from the folder where your .json file is, or specify the full path to the input .json file. Taking a guess based on your info above, that path is likely C:\Users\kate\Documents\TESTESTESTEST\PiggyButton.json.

It worked!!! Thank you!

don't convert path const percentage and mix parametrs on last Skeleton Viever from 3.8 to 3.7

I'm trying to convert my Spine animation jsons from 3.7 to 3.6
using this instrution (and skeletonViewer 3.7), and it doesn't work.

It creates a file with a plain name "3.6" (no extension), and it's a json with previous version.

@momijigari With the JsonRollback tool you can specify either 2.1 or 3.7 to perform the following conversions:

2.1: supports going from version 3.3.xx to 2.1.27.
3.7: supports going from version 3.8.xx to 3.7.94.

It's been a long time, but if I remember correctly, there's not much (or any) difference between 3.7 and 3.6 JSON. Are you sure you need to do a conversion?

Thank you, Nate.

So I can convert to just 2 versions of Spine?

My problem is that we have been doing all animations in Spine 3.7.94
But my customer's game engine supports 3.6.53, and they require exports for 3.6.53
And not all animations can be manually converted to 3.6 (by exporting JSON from 3.7 and then importing those into 3.6 Spine), some just don't import.
So I'm tryin to find a solution here.

We would have to first determine why your 3.7 JSON doesn't import into 3.6. Can you post or email one of the problematic JSON files? contact@esotericsoftware.com

Hi, I'm trying to export json file from the spine 4.0.51 to 3.8, but I am getting this result on terminal here on my mac:

Error: Could not find or load main class com.esotericsoftware.spine.JsonRollback
Caused by: java.lang.ClassNotFoundException: com.esotericsoftware.spine.JsonRollback

Sorry, you cannot go from 4.0 to an earlier version. 4.0 stores the curve information in ways that cannot be represented in older versions.

Hi, I'm trying to convert a file from version 3.8.99 to 3.7, but it gives me the following error:
Error: Could not find or load main class com.esotericsoftware.spine.JsonRollback

I have the skeletonViewer-beta.jar file in the same folder as the file I want to convert and I just installed Java

@javier_mh94 Sorry about that, we've uploaded Skeleton Viewer 4.0.53-beta which fixes that problem.

Thanks Nate! Now it works perfectly