In general there is no culling performed in the Spine runtimes to check individual attachments for visibility on screen. So animation and mesh generation will animate and output all your enabled attachments to the generated unity Mesh.
What should make a difference however is on Unity's side, what will happen with one vs multiple Meshes:
- If you are using a single CanvasRenderer, then nothing will be culled.
- If you are however having multiple CanvasRenderers active (
Advanced - Multiple CanvasRenderers in the Inspector), then Unity should be able to perform culling tests on each single Mesh. So you could use a SkeletonRenderSeparator to split your skeleton in grouped parts.
Please be sure to perform some testing first if you really consider going down the second road.
