How to build/modify a scene from files

glTF
#1

Hello everyone, first of all you should note that I am a total newbie when it comes to glTF, I would appreciate any help with these questions:

1 - In the structure of a glTF file, must there be a specific order of the arrays?
for example, “meshes” must come before or after “accessors”, or does it not matter?

2 - Do the declarations of each type of array have to be only once with all the declarations together or could I “partition” them? for example, could I have the “meshes” declaration like this?

"meshes" : [
       {
           "name" : "mesh1",
           "primitives" : [
                blablabla
           ]
       },
]

"accesors" : [
blablabla
]


"meshes" : [
       {
           "name" : "mesh2",
           "primitives" : [
                blablabla
           ]
       },
]

3 - Is there any tool (GUI or by command) to join 2 glTF by manipulating the content of the files, I know it can be done by copy & paste but, maybe, some tool that helps with the modification of the references to the indexes and the data offsets?

Thanks in advance.
D.

#2

JSON associative arrays do not have ordering. This is a fundamental part of the file format. Since glTF is based on JSON, it carries this over.

#3

2 - Do the declarations of each type of array have to be only once…

Duplicate keys in the same top-level JSON object would be a problem, you’ll want to avoid that.

3 - Is there any tool (GUI or by command) to join 2 glTF by manipulating the content of the files, …

You could import multiple glTF files into Blender and then export the whole scene to one glTF. The gltf-transform scripting library or CLI would also be an option:

gltf-transform merge a.glb b.glb output.glb

When working with glTF files in a programming language, you’ll probably want to at least use a library for reading/writing JSON, or even a library designed for reading/writing glTF. VSCode also has a plugin for viewing, editing, and validating glTF JSON by hand.