No, I'm afraid it has to be done from the command line or with a shell script.

What we did, to kinda sorta solve this, is make sure all the attachments of a single skin are in their own folder (no reusing of the same attachment) and afterwards pakc those folders separately using the command line.

Understood. As mentioned, we will consider a way to do it without the extra steps. The workaround described above is a stopgap until then. While I also wouldn't suggest asking animators to write terminal commands, it may be acceptable for them to run a shell script that does the necessary steps for them.

However, I do believe that automating export can be beneficial in many cases. In general, it can be error prone to trust people (animators, programmers, or anyone else) to both remember to do the exports when project files change and to do all the exports with the right settings, to the right place, etc. Also, often a build is not just processing Spine projects

usually all but the simplest of applications has a fair amount of tasks that can be automated to reduce errors and save time.

How do I get the command line packer NOT to create multiple atlas based on folders?

My command is like this:
Spine -i image_folder/ -o "output_path" -n set1 -p polygon_halfsize.pack.json

There seems no way to tell the packer to ignore folders and pack everything into one big atlas. I have skin folders of characters and some common folders which contains shared images among skins. I want to use symbolic link to prepare image folders which can skip copying images every time doing the export.

Besides the single atlas issue, I got a lot of "Missing Region" warning but I already unchecked "export" for the unrelated skins. I found that the export.json seems doesn't even saved which skins should be ignored thus causing the "Missing Region" warning in unity. It try to get the attachment which should be excluded from the export.

Note folders give you one atlas with multiple atlas page images, not multiple atlases.

You can use the "combine subdirectories" setting to pack images in folders (subdirectories) into the same atlas page. If they don't fit they will spill over into subsequent pages.

When you run the texture packer on a folder of images, it just packs the images found. Unchecking Export for a skin causes that skin and its attachments to not be written in exported JSON or binary data. You can inspect the JSON and make sure that is the case. The only reason you should ever get "missing region" messages in Unity is that there are attachments in the data that don't have a matching texture region in the atlas.

Nate wrote

You can use the "combine subdirectories" setting to pack images in folders (subdirectories) into the same atlas page. If they don't fit they will spill over into subsequent pages.

Just found that the latest version has this option missing. No wonder why I don't find it.

Unchecking Export for a skin causes that skin and its attachments to not be written in exported JSON or binary data. You can inspect the JSON and make sure that is the case. The only reason you should ever get "missing region" messages in Unity is that there are attachments in the data that don't have a matching texture region in the atlas.

Exactly, the xxx.export.json didn't store which skin to ignore. Thus, when exporting from command line using that export.json file , all skins are exported. That's the issue. Alhought exporting directly from spine UI mode works, it would not be easy because for each skin, user has to manually adjust the ignore list for the skins.

Here is the saved export.json file. Not mentioning the export-unchecked skins at all.

{
"class": "export-binary",
"name": "Binary",
"project": "Kids.spine",
"output": "D:/exports/Units/Npc/HarbourKids",
"open": false,
"extension": ".skel.bytes",
"nonessential": false,
"cleanUp": false,
"packAtlas": {
   "stripWhitespaceX": true,
   "stripWhitespaceY": true,
   "rotation": true,
   "alias": true,
   "ignoreBlankImages": false,
   "alphaThreshold": 3,
   "minWidth": 16,
   "minHeight": 16,
   "maxWidth": 2048,
   "maxHeight": 2048,
   "pot": true,
   "multipleOfFour": false,
   "square": false,
   "outputFormat": "png",
   "jpegQuality": 0.9,
   "premultiplyAlpha": true,
   "bleed": false,
   "scale": [ 0.5 ],
   "scaleSuffix": [ "_half" ],
   "scaleResampling": [ "bicubic" ],
   "paddingX": 1,
   "paddingY": 1,
   "edgePadding": true,
   "duplicatePadding": false,
   "filterMin": "Linear",
   "filterMag": "Linear",
   "wrapX": "ClampToEdge",
   "wrapY": "ClampToEdge",
   "format": "RGBA8888",
   "atlasExtension": ".atlas.txt",
   "combineSubdirectories": false,
   "flattenPaths": false,
   "useIndexes": false,
   "debug": false,
   "fast": false,
   "limitMemory": true,
   "currentProject": true,
   "packing": "polygons",
   "silent": false,
   "ignore": false,
   "bleedIterations": 2
},
"packSource": "attachments",
"packTarget": "perskeleton",
"warnings": true
}

I changed the combineSubdirectories to true directly from .json file. It works, now only output one PNG.

However, when try to export directly from Spine Editor instead of command line. It has error.
The HomeTown_Girl skin has "export" unchecked and it blame not being able to find it.

Spine Launcher 3.8.82
Esoteric Software LLC (C) 2013-2020 | http://esotericsoftware.com
Windows 10 Enterprise x86 10.0
Spine 3.8.93 Professional
Licensed to: Secret
Pack: skeleton
Complete.
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               ERROR: Unable to export:
java.lang.RuntimeException: java.lang.RuntimeException: Skin not found in skeleton: HomeTown_Girl
   at OT.Z(SourceFile:1858)
   at CF.S(SourceFile:48)
   at AP.run(SourceFile:671)
   at java.base/java.lang.Thread.run(Unknown Source)
Caused by: java.lang.RuntimeException: Skin not found in skeleton: HomeTown_Girl
   at sX.S(SourceFile:853)
   at sX.S(SourceFile:428)
   at sX.S(SourceFile:103)
   at sX.S(SourceFile:123)
   at CH.run(SourceFile:60)
   at OV.run(SourceFile:1846)
   at cOM9.S(SourceFile:289)
   at Com2.run(SourceFile:252)
   at java.desktop/java.awt.event.InvocationEvent.dispatch(Unknown Source)
   at java.desktop/java.awt.EventQueue.dispatchEventImpl(Unknown Source)
   at java.desktop/java.awt.EventQueue.access$600(Unknown Source)
   at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
   at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
   at java.base/java.security.AccessController.doPrivileged(Native Method)
   at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
   at java.desktop/java.awt.EventQueue.dispatchEvent(Unknown Source)
   at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
   at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
   at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
   at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
   at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
   at java.desktop/java.awt.EventDispatchThread.run(Unknown Source)

Nothing about skins will ever be in the export JSON or texture packing setting JSON. Whether a skin is exported is only stored in the .spine project file.

There are two ways to export an atlas:
Texture Packing - Spine User Guide

1) Packing during skeleton data export
When doing this, there is no option to combine subdirectories because Spine is packing only the images actually used by the skeleton

subdirectories/folders are not being used at all to find images or decide which images go on what atlas page (which also means pack.json in your image folders files are not used). I will make a note about this setting not being shown when packing in this mode.

You get this mode when you check Pack while doing binary or JSON export AND you choose Attachments. When you export from the command line, you'd use the `

exportor-e` options with an export settings JSON file.

Note this option is for convenience, to quickly get an atlas for a skeleton, or for simple projects that don't need more control.

2) Using the Spine Texture Packer separately
When doing this, folders are used to determine which pages images are written to and combine subdirectories can be set.

You get this mode when you run the texture packer separately, not as part of binary or JSON export. When you export from the command line, you'd use the `

packor-p` options with a texture atlas settings JSON file.

Note this option gives more control over how packing is done (via folders, combine subdirectories, and pack.json files, you can pack images for multiple skeletons into the same atlas, etc).

The export settings JSON you showed is for binary export with texture atlas packing (#1). Everything will be packed in one page, if it fits.

Using the "kids" project you posted in another thread, I reproduced the error log you showed by unchecking Export for HomeTown_Girl. It happens for me in the UI. I didn't try the CLI, but seeing it is sufficient for us to fix it. From a quick look, it happens during export of a deform timeline for a mesh attachment in the skin that is not being exported. The fix is easy (we should just skip such timelines). We'll do a 3.8 release in a day or two, in case there are other fixes needed for 3.8.

With that fixed, I notice the atlas still contains HomeTown_Girl/* images. I think there is another bug that doesn't respect the skin Export being unchecked. It should not include those images in the atlas when packing. We'll get that fixed too!

Sorry for the trouble with bugs you are having lately! We really do appreciate that you are taking the time to help us reproduce and fix them.

Hmm. For the export checkbox on attachments, if the attachment is keyed in an animation, it is exported anyway and a warning is shown. I honestly don't remember when we added an export checkbox for skins, so we'll have to think on how that should behave.

To follow up, in 3.8.94 we've fixed a number of bugs with export checkboxes for attachments and skins, and changed how they work for attachments slightly. :greatsuccess: