關閉標題：glb 切成細的 b3dm glb 要自己先切碎
內容：

pip install pygltflib 
要自己先切碎
# glbtosplitglb.py
from pygltflib import GLTF2

# 讀取原始 GLB
gltf = GLTF2().load("28.glb")

# 假設按 mesh 拆
for i, mesh in enumerate(gltf.meshes):
    new_gltf = GLTF2()
    new_gltf.meshes.append(mesh)
    
    # node 必須指向這個 mesh
    new_gltf.nodes.append(gltf.nodes[i])
    new_gltf.scenes = gltf.scenes
    new_gltf.save(f"tile_{i}.glb")



glb 轉成 b3dm
mkdir -p b3dm_tiles

for f in tile_*.glb; do
    filename=$(basename "$f" .glb)
    npx 3d-tiles-tools glbToB3dm --input "$f" --output "b3dm_tiles/${filename}.b3dm" --force
done


多執行緒
ls tile_*.glb | parallel -j 4 'filename=$(basename {} .glb); npx 3d-tiles-tools glbToB3dm --input {} --output b3dm_tiles/${filename}.b3dm --force'