[Bug] Bone with rotation bug

[hef-sus]

✔️ Pre-check

• [✔️ ] Tested with the latest snapshot of BetterModel from Modrinth
• [ ✔️] Confirmed the issue occurs without other optional/experimental plugins or clients (see Disclaimer below)

---

🐞 Problem Description

mentioned on https://github.com/toxicity188/BetterModel/issues/347

i have a head bone hi_head, a chilren bone inside hi_head with rotation
when i move my head up and down (pitch) , that bone rotate weirdly

---

📜 Server Log

Your error log if exists.

---

🖼️ Screenshot / Video

Minecraft_.1.21.11.-.Multiplayer.3rd-party.Server.2026-05-30.17-01-54.mp4

---

🧪 Test Model / Code

Upload the model, resource pack, or test code that can reproduce the issue if possible.

---

🌍 Environment

• OS: (Windows, Linux, etc.)
• Server software & version: (Paper 1.21.1, etc.)

---

Disclaimer

The following environments are not supported, and issues occurring under these conditions will not be handled:

- Informal / modified launchers (e.g., Feather client)
- Closed-source mods/plugins (Optifine, ItemsAdder, Nexo, etc.)
- Hybrid server platforms (e.g., Arclight)

[toxicity188]

Please keep the visual presentation in mind for the numerous other users who visit this issue page