I am messing around with Unity and the LPC Spritesheet Collection.

The LPC sprites are a set of artworks all of the same size and the same amount of animations. I can create animations for it no problem, when I do it manually.

My issue is: LPC has a lot of different character bodies (skin colors, different races), since they are of the same size and have the same animations in the same way, I was trying to create an AssetPostProcessor extension that would create the animations automatically when I import a LPC image into my project.

I am already able to slice the spritesheets correctly with this Script I found, and I can create and save the animation clips based on the spritesheets. The clips have the correct length and configuration, but the sprites for each frame seem to be empty! Take a look at the image below...

enter image description here

This is the piece of code that generates the animations from the sprite meta datas:

    for (int col = 0; col < m_ColCount; ++col)
        SpriteMetaData meta = new SpriteMetaData();
        meta.rect = new Rect(col * LPC_SPRITE_SIZE, row * LPC_SPRITE_SIZE, LPC_SPRITE_SIZE, LPC_SPRITE_SIZE);

// I skipped some code for renaming and checking for empty sprite frames for brevity...

EditorCurveBinding spriteBinding = new EditorCurveBinding();
        spriteBinding.type = typeof(SpriteRenderer);
        spriteBinding.path = "";
        spriteBinding.propertyName = "m_Sprite";

    ObjectReferenceKeyframe[] spriteKeyFrames = new ObjectReferenceKeyframe[currentLoops.Count];
    for (int i = 0; i < currentLoops.Count; i++)
        spriteKeyFrames[i] = new ObjectReferenceKeyframe();
        spriteKeyFrames[i].time = i;
        spriteKeyFrames[i].value = currentLoops[i];

    AnimationClip clip = new AnimationClip();
    clip.name = animState.ToString();
    clip.frameRate = currentLoops.Count;

    AnimationUtility.SetObjectReferenceCurve(clip, spriteBinding, spriteKeyFrames);

    if(!changesToSave.ContainsKey("Assets/Sprites/" + clip.name + ".anim"))
        changesToSave.Add("Assets/Sprites/" + clip.name + ".anim", clip);

    Debug.Log("Added " + clip.name);
TextureImporter textureImporter = (TextureImporter)assetImporter;
textureImporter.spritesheet = metas.ToArray();

And I am saving the sprites in the OnPostProcessSprites callback like this:

Debug.Log("Sliced Sprites: " + sprites.Length);

foreach (var key in changesToSave.Keys)
    AssetDatabase.CreateAsset(changesToSave[key], key);

var textureImporter = (TextureImporter)assetImporter;
  • 2
    \$\begingroup\$ If there's no difference between the animation data for each of these sets of sprites, then you might not want to create new animations at all. Setting up a script to always run the same animation, but swap the sprites displayed, would likely be more efficient. \$\endgroup\$
    – DMGregory
    Commented Feb 2, 2020 at 21:52
  • \$\begingroup\$ @DMGregory hmmm sounds interesting, but how would that work? I know I can set the sprite in the spriterenderer component, but how would I do that with a sliced spritesheet? \$\endgroup\$ Commented Feb 2, 2020 at 22:21
  • \$\begingroup\$ @DMGregory Thanks for your insight, I figured it out and implemented my own sprite swapper for this case! \$\endgroup\$ Commented Feb 3, 2020 at 0:25
  • \$\begingroup\$ I'd recommend editing your question to something like "How do I animate many sets of sprites with the same animation?" And add the solution you developed as an Answer. \$\endgroup\$
    – DMGregory
    Commented Feb 3, 2020 at 2:15


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