Behind the 3D scenes - part1

g3dj structure

{
    "version": [  0,   1], 
    "id": "", 
    "meshes": [
...
    ], 
    "materials": [
...
    ], 
    "nodes": [
...
    ], 
    "animations": []
}

https://xoppa.github.io/blog/behind-the-3d-scenes-part1/
需要深入研究，明白各个数组的意思