Copying transforms from one object to another

Question

I am working on a virtual production app, and I need to be able to copy the transforms of one GameObject and all of its children to another. I asked previously here how to animate a character moving while allowing outside motion to override it, and it was suggested that I make a hidden copy of the character and transfer the positions of the bones to the main character in LateUpdate. Is there a way to copy all of the bone positions from one GameObject to another?

Answer 1

Something like this?

public static void CopyTransformTree(Transform sourceRoot, Transform destRoot) {
    // Read local pose in one operation.
    sourceRoot.GetLocalPositionAndRotation(out var localPos, out var localRot);
    // Clone local pose to destination transform in one operation.
    destRoot.SetLocalPositionAndRotation(localPos, localRot);

    // Clone scale (skip if your bones don't use scale).
    destRoot.localScale = sourceRoot.localScale;

    // Iterate over as many children as both roots have.
    int limit = Mathf.Min(sourceRoot.childCount, destRoot.childCount);
    for (int i = 0; i < limit; i++) // Recurse on each child sub-tree.
        CopyTransformTree(sourceRoot.GetChild(i), destRoot.GetChild(i));
}

void LateUpdate() {
    CopyTransformTree(sourceRootBone, destRootBone);
}

Answer 2

You can copy the transforms of one GameObject and all of its children to another using the Transform class's methods.

public void CopyTransforms(Transform sourceTransform, Transform targetTransform)
{
    // Copy the position, rotation, and scale of the source transform to the target transform
    targetTransform.position = sourceTransform.position;
    targetTransform.rotation = sourceTransform.rotation;
    targetTransform.localScale = sourceTransform.localScale;

    // Copy the positions, rotations, and scales of all child transforms recursively
    foreach (Transform sourceChild in sourceTransform)
    {
        Transform targetChild = targetTransform.Find(sourceChild.name);
        if (targetChild)
        {
            CopyTransforms(sourceChild, targetChild);
        }
    }
}
```