Yes, per attachment color is a recent feature and hasn't been implemented in most runtimes yet, sorry. It allows attachments in skins to have different colors.

The "path" field for region attachments (also not in runtimes) is related, which allows the same image to be in a slot twice (same path, different name). This allows the same attachment to be in a slot multiple times, with different colors or offset SRT. This is needed for meshes, which you may want in a slot multiple times with a different deformation.

Until it's implemented you can do it with code...

Color blackTint = new Color(0f,0f,0f,1.0f);

	Spine.Skeleton skeleton = yourSkeletonAnimation.skeleton;

	foreach (Spine.Slot slot in skeleton.slots) {
	
		//either tint by slot name

		if(slot.ToString().Contains("hand")){
			slot.R = blackTint.r;
			slot.B = blackTint.b;
			slot.G = blackTint.g;
			slot.A = blackTint.a;
		}


		//or by attachment name


		if(slot.Attachment!=null){
			if(slot.Attachment.Name.Contains("hand")){
				slot.R = blackTint.r;
				slot.B = blackTint.b;
				slot.G = blackTint.g;
				slot.A = blackTint.a;
			}
		}
	}

Hello,
Sorry to dig this problem, but I don't think this is implemented yet and I tried the code above. It works well in the SpineBoy example but not with an homemade animation, and I really don't understand why. Do you have an idea why or an advice about where I can search ?

Thanks,

It is implemented, should work. What doesn't work?

For an animation, every slot has a new color.
When I played this animation in Spine, the color appears correctly (on the character and in the Draw Order tree).

This color is in the .json file ({"Crete":{"color":[{"time":0,"color":"ffffffff"},{"time":0.0333,"color":"ff8e8aff"},...). But when the animation is played in unity (via skeleton.state.SetAnimation()), the color doesn't appear (with or without the code above).

Thank you for taking the time to help me

You are using the Skeleton shader?

I really don't know what you are talking about, I am so sorry. I also see now, that the title contains the tk2d package, but I don't use it (juste spine-csharp and spine-unity). Do I have to use it ? (if yes, I have some trouble to made unity works with it because spine-unity contains the same class as it, and juste with spine-tk2d it doesn't compile). Thanks for your time.

It should work in Spine-Unity.

The Shader is something you pick on the Material asset of your character.

If you don't know what Shader and Material are, look them up in the Unity documentation.
It might help clear things up in the future.

But slot coloring relies a few things, including using a compatible shader. Spine comes with Spine/Skeleton shader and if you have that and are using the latest runtime, and didn't do anything weird in the Spine animations, slot colors should work.

I am so ashamed, I was searching in the code, not in Unity.
I changed the shader in the material (from transparent/diffuse to Spine/Skeleton), and it works.
I can't thank you enough !!