Squirrel Transfer Format - Experimental Modular 3D Interchange Format [version 0.0.0]
Intended for (not only) game development use-cases.
In development for: |
Godot (TBD soon) |
Try to import this example model!
Very relevant future implementation targets include: 3dsMax, Unreal Engine, Maya, Bevy, BabylonJs, …
This repository hosts the documentation for the STF format and core modules.
STF by itself is merely a shell format. It provides a framework for different modules to parse and serialize resourses.
Resources are stored as Json-objects, identified by a unique ID. Resources can reference binary buffers and each other.
A few modules, including but not limited to stf.prefab, stf.node, stf.mesh and stf.material, are provided by default.
Additional modules can be easily implemented by third parties. Each STF implementation provides an easy and convenient way to hot-load module-plugins.
Similar to glTF 2.0, an STF file consists of a Json definition and binary data. Contrary to glTF, STF is firmly intended for interchange of 3d assets, not runtime loading or asset-streaming.
Game-engines are responsible for runtime optimization, not the 3d file format or 3d modeling tool.
Minimal example Json definition
{
"stf": {
"version_major": 0,
"version_minor": 0,
"root": "50695120-9637-4a9f-be77-bfa3b06504f8",
"profiles": [],
"asset_info": {
"asset_name": "Default Cube"
},
"generator": "stf_blender",
"generator_version": "0.0.1",
"timestamp": "2025-06-17T15:43:23.736748+00:00",
"metric_multiplier": 1
},
"resources": {
"26dc0d69-1ae8-4397-9620-adcbf4d78d8e": {
"type": "stf.material",
"name": "Material",
"properties": {
"albedo.color": {
"type": "color",
"values": [
[
0.800000011920929,
0.800000011920929,
0.800000011920929,
1.0
]
]
},
"roughness.value": {
"type": "float",
"values": [
0.5
]
},
"metallic.value": {
"type": "float",
"values": [
0.0
]
}
},
"style_hints": [
"realistic",
"pbr"
],
"shader_targets": {
"stfblender": [
"ShaderNodeBsdfPrincipled"
]
}
},
"d37b3ebb-cfd3-4862-b411-5a204d69c890": {
"type": "stf.mesh",
"name": "Cube",
"material_slots": [
"26dc0d69-1ae8-4397-9620-adcbf4d78d8e"
],
"float_width": 4,
"indices_width": 1,
"vertices": "d00a096e-4326-4fdb-bf02-eb3de813e84f",
"vertex_color_width": 4,
"colors": [],
"splits": "2dae3757-6ce4-4119-968c-397ee0ce105f",
"split_normals": "4c25c590-7a8b-4a88-bf42-f4f7c34cdef4",
"split_tangents": "538c4eb6-eeca-476b-a929-c3649157a81f",
"uvs": [
{
"name": "UVMap",
"uv": "be2b2b11-85bc-4beb-9cff-880946e137bf"
}
],
"split_colors": [],
"tris": "a57a4aea-a62a-4de1-af00-1942ee555bee",
"material_indices_width": 1,
"faces": "2222c1fc-2a27-4d0b-843a-d835878559f8",
"material_indices": "33607654-7624-4a63-9ddf-c1dbba31589d",
"sharp_face_indices": "7f2c36a2-dbd8-4b73-b8a9-d52ed3b78ca7",
"lines": "469abcd8-fdcf-485c-b2c6-6faf2bf84150",
"sharp_edges": "635c99eb-00ae-4066-b5ad-1b7d1e4c54f3",
"components": [
"2a4a7084-0df6-4a01-b25f-09de8825defd"
]
},
"2a4a7084-0df6-4a01-b25f-09de8825defd": {
"type": "stfexp.mesh.seams",
"seams_len": 0,
"seams": "e3cc3cbf-a72d-448a-b9d4-51db25909d58"
},
"46de4bce-c119-404e-8348-43ac53c8317d": {
"type": "stf.instance.mesh",
"mesh": "d37b3ebb-cfd3-4862-b411-5a204d69c890",
"materials": [
"26dc0d69-1ae8-4397-9620-adcbf4d78d8e"
],
"blendshape_values": []
},
"0585218b-dc88-4a9b-b7e5-c67a40a988a6": {
"type": "stf.node",
"name": "Cube",
"children": [],
"trs": [
[
0.0,
0.0,
-0.0
],
[
0.0,
0.0,
-0.0,
1.0
],
[
1.0,
1.0,
1.0
]
],
"instance": "46de4bce-c119-404e-8348-43ac53c8317d"
},
"c76b3b6f-8ef6-444a-91e6-137000d12f0e": {
"type": "stf.node",
"name": "Light",
"children": [],
"trs": [
[
4.076245307922363,
5.903861999511719,
-1.0054539442062378
],
[
0.16907574236392975,
0.7558803558349609,
-0.27217137813568115,
0.570947527885437
],
[
1.0,
1.0,
0.9999999403953552
]
]
},
"9a05989b-ca4f-4cef-baa3-952564e705da": {
"type": "stf.node",
"name": "Camera",
"children": [],
"trs": [
[
7.358891487121582,
4.958309173583984,
6.925790786743164
],
[
0.483536034822464,
0.33687159419059753,
-0.20870360732078552,
0.7804827094078064
],
[
1.0,
1.0,
1.0
]
]
},
"50695120-9637-4a9f-be77-bfa3b06504f8": {
"type": "stf.prefab",
"name": "Collection",
"root_nodes": [
"0585218b-dc88-4a9b-b7e5-c67a40a988a6",
"c76b3b6f-8ef6-444a-91e6-137000d12f0e",
"9a05989b-ca4f-4cef-baa3-952564e705da"
],
"animations": []
}
},
"buffers": {
"d00a096e-4326-4fdb-bf02-eb3de813e84f": {
"type": "stf.buffer.included",
"index": 0
},
"2dae3757-6ce4-4119-968c-397ee0ce105f": {
"type": "stf.buffer.included",
"index": 1
},
"4c25c590-7a8b-4a88-bf42-f4f7c34cdef4": {
"type": "stf.buffer.included",
"index": 2
},
"538c4eb6-eeca-476b-a929-c3649157a81f": {
"type": "stf.buffer.included",
"index": 3
},
"be2b2b11-85bc-4beb-9cff-880946e137bf": {
"type": "stf.buffer.included",
"index": 4
},
"a57a4aea-a62a-4de1-af00-1942ee555bee": {
"type": "stf.buffer.included",
"index": 5
},
"2222c1fc-2a27-4d0b-843a-d835878559f8": {
"type": "stf.buffer.included",
"index": 6
},
"33607654-7624-4a63-9ddf-c1dbba31589d": {
"type": "stf.buffer.included",
"index": 7
},
"7f2c36a2-dbd8-4b73-b8a9-d52ed3b78ca7": {
"type": "stf.buffer.included",
"index": 8
},
"469abcd8-fdcf-485c-b2c6-6faf2bf84150": {
"type": "stf.buffer.included",
"index": 9
},
"635c99eb-00ae-4066-b5ad-1b7d1e4c54f3": {
"type": "stf.buffer.included",
"index": 10
},
"e3cc3cbf-a72d-448a-b9d4-51db25909d58": {
"type": "stf.buffer.included",
"index": 11
}
}
}Previously, a proof-of-concept for such a format has been made here: Repository Link
This repository is licensed under CC-BY-4.0 (https://creativecommons.org/licenses/by/4.0/)