It’s a 3d element.
It may be a primitive or a light.
All elements must have a type property with its type.

Examples

• {
      "type": "sphere",
      "coords": [
          [[0, 0, 0]]
      ],
      "color": [1, 1, 1], // white
      "radius": 1
  }
  

• {
      "type": "ambient", // ambient light
      "color": [0.5, 0.5, 0.5] // gray
  }