Meshes `info` file contains field not defined in the neuroglancer specification

[LucaMarconato]

I have just noticed that the info file for meshes created via igneous (I am creating sharded meshes), contain some fields (chunk_size, spatial_index) that are not defined in the mesh precomputed format specification. For example, this is a file that was created by igneous (I formatted the json to add the indentation):

My understanding is that those values reflect how the data was created, and so knowing them can be useful. On the other hand neuroglancer does not seem to require them, which could create confusion.

{
    "@type": "neuroglancer_multilod_draco",
    "mip": 0,
    "chunk_size": [
        40,
        40,
        40
    ],
    "spatial_index": {
        "resolution": [
            100,
            100,
            100
        ],
        "chunk_size": [
            4000,
            4000,
            4000
        ]
    },
    "vertex_quantization_bits": 16,
    "transform": [
        100,
        0,
        0,
        0,
        0,
        100,
        0,
        0,
        0,
        0,
        100,
        0
    ],
    "lod_scale_multiplier": 1.0,
    "sharding": {
        "@type": "neuroglancer_uint64_sharded_v1",
        "preshift_bits": 0,
        "hash": "murmurhash3_x86_128",
        "minishard_bits": 0,
        "shard_bits": 0,
        "minishard_index_encoding": "gzip",
        "data_encoding": "raw"
    }
}

[william-silversmith]

Hi Luca,

Thanks for writing in! It would be possible to use a separate file to track these attributes, but it also makes things slightly more complicated too. I'll keep it in mind, but for the time being I won't be making any changes.

Will