Why does this avatar importer custom attachment not move?

[sudachipapa]

I would like to use the avatar importer plugin to import a custom animated avatar, with attachments. However when I try to do so, the attachment does not move with the rest of the animation.

Here is a minimal example of the problem:
avatar_importer_custom_attachment.rbxl (43.0 KB)
avatar_importer_custom_attachment.blend (790.1 KB)
avatar_importer_custom_attachment.fbx (59.9 KB)

In the files above, I have animated a cube in Blender and exported it as .fbx, imported it into Studio, imported the animation, and finally played it with a script:

You can see that the attachment is present (little green ball), but it does not move:

In Blender, the attachment does move:

Eventual purpose is to add hats to my cat game, which uses custom skinned meshes. Consequence of this problem was that the cats could wear hats, but the hats do not follow head movement.

How do I make the attachment move with the animation?

[kleptonaut]

An attachment on the Part doesn’t work because the part has no simulated movement (The CFrame of the part does not change), it’s only animating. If you want to capture the animated movement, that comes from the Bones.

You can add a new Bone and parent it to “TopBone” and offset its position from that bone how you’d like.