Export Unity Animation Positions

2024-01-24 19:58 UTC gpt-4 Open in ChatGPT ↗

You

I want to process all frames of a humanoid animation and access all the positions of all limbs in a Unity script, outside the runtime. I am not interested in playback, just the export of all positions. How to achieve this using a c# script?

ChatGPT

To export all positions of limbs from a humanoid animation in Unity using a C# script, you’ll need to perform the following steps. Note that this process is somewhat complex and requires a good understanding of Unity’s animation system and scripting.

1. Access the Animation Clip: First, you need to get the AnimationClip you want to process. This can be done by referencing the clip directly or finding it in an Animator component.

2. Iterate Through Frames: Unity animations are usually defined in terms of keyframes and Unity does not provide a direct way to iterate over each frame. However, you can simulate this by updating the animation time and sampling the clip.

3. Sample Animation at Each Frame: For each frame, you need to manually sample the animation to update the bone transforms.

4. Access Bone Transforms: Once the animation is sampled, you can access the transforms of the bones you are interested in. In a humanoid rig, these can be accessed through the Animator component using GetBoneTransform.

5. Record Positions and Rotations: For each bone of interest, record its position and rotation. You may want to convert these to a global space depending on your needs.

6. Export Data: Finally, write this data to a file or another format that suits your needs, like JSON, XML, or CSV.

7. Automate for All Frames: Wrap this process in a loop that changes the animation time and samples the clip for each frame.

Here’s a rough outline of how the script might look like:

using UnityEngine;
using System.IO;
using System.Collections.Generic;

public class AnimationExporter : MonoBehaviour
{
    public AnimationClip clip;
    public Animator animator;

    void Start()
    {
        ExportAnimationData(clip);
    }

    void ExportAnimationData(AnimationClip clip)
    {
        // Assuming 60fps, adjust as needed
        float frameTime = 1f / 60f;
        float clipLength = clip.length;

        var data = new List<string>();

        for (float t = 0; t < clipLength; t += frameTime)
        {
            clip.SampleAnimation(gameObject, t);

            // Access each bone transform
            foreach (HumanBodyBones bone in System.Enum.GetValues(typeof(HumanBodyBones)))
            {
                if (bone == HumanBodyBones.LastBone) continue;

                Transform boneTransform = animator.GetBoneTransform(bone);
                if (boneTransform != null)
                {
                    Vector3 position = boneTransform.position;
                    Quaternion rotation = boneTransform.rotation;

                    // Record the data
                    data.Add($"{bone}: Position={position}, Rotation={rotation}");
                }
            }
        }

        File.WriteAllLines("ExportedAnimationData.txt", data);
    }
}

Important Considerations:

• This script should be executed in the Unity Editor, not at runtime.
• The frame rate (frameTime in the script) should match the frame rate of your animation.
• This script writes data to a text file. You may want to adjust the format or the way data is exported based on your requirements.
• Ensure that the GameObject to which this script is attached has the correct Animator component and that the animator is configured with the correct avatar and animations.
• If your animation involves IK or other procedural animations, this might not be captured accurately with this method.

Remember, this is a basic outline. You’ll likely need to tailor the script to fit your specific needs and handle any edge cases or specific requirements of your project.