.NET 6 Library for reading/writing 3D Tiles B3dm files to/from glTF 2.0

Batched 3D specification: https://github.com/AnalyticalGraphicsInc/3d-tiles/blob/master/specification/TileFormats/Batched3DModel/README.md

In this sample the payload of a B3DM tile is converted to GLB file.

Sample code:

var inputfile = @"testfixtures/662.b3dm";
var outputfile = Path.GetFileNameWithoutExtension(inputfile) + ".glb";
var f = File.OpenRead(inputfile);
var b3dm = B3dmReader.ReadB3dm(f);
var stream = new MemoryStream(b3dm.GlbData);
File.WriteAllBytes(outputfile, stream.ToArray());

var inputfile = @"testfixtures/building.glb";
var buildingGlb = File.ReadAllBytes(inputfile);
var b3dm = new B3dm.Tile.B3dm(buildingGlb);
var bytes = b3dm.ToBytes();
File.WriteAllBytes("test.b3dm", bytes);

• .NET 6

BenchmarkDotNet=v0.12.1, OS=Windows 10.0.19041.329 (2004/?/20H1)
Intel Core i7-9750H CPU 2.60GHz, 1 CPU, 12 logical and 6 physical cores
.NET Core SDK=3.1.301
  [Host]     : .NET Core 3.1.5 (CoreCLR 4.700.20.26901, CoreFX 4.700.20.27001), X64 RyuJIT
  DefaultJob : .NET Core 3.1.5 (CoreCLR 4.700.20.26901, CoreFX 4.700.20.27001), X64 RyuJIT

|    Method |      Mean |    Error |    StdDev |    Median |   Gen 0 |   Gen 1 |   Gen 2 | Allocated |
|---------- |----------:|---------:|----------:|----------:|--------:|--------:|--------:|----------:|
|  ReadB3dm |  40.81 us | 0.930 us |  2.742 us |  39.88 us | 13.6719 |  0.2441 |       - |   85.1 KB |

2024-01-25: Version 1.1.2, fix glb length

2023-02-16: Version 1.1.1, remove trailing byte padding when reading Glb

2023-01-18: Version 1.1, namespace changes from B3dm.Tile to B3dmCore

2023-01-11: Version 1.0.2, fix glb length

2023-01-11: Version 1.0.1, adding padding for GLB

2022-12-08: Version 1.0, to .NET 6

2021-10-27: Version 0.14, adding non latin batchtable support

2020-11-02: Version 0.13, supporting cmpt tiles

2020-08-03: Version 0.10 + 0.11 + 0.12 breaking change: B3dmWriter for writing to file removed, use b3dm.ToBytes() instead

2020-07-01: Version 0.9 adding 8 byte padding rules

2019-07-10: Version 0.8

• adding featuretable / batchtable support (json and binary formats) for reading and writing b3dm tiles

2019-07-05: Version 0.7

2019-05-16: Version 0.6

2019-05-09: version 0.5

• Added pack glb file to b3dm

2019-01-09: version 0.4.1

• Added parsing FeatureTableJson, FeatureTableBinary, BatchTableJson, batchTableBinary

2019-01-09: version 0.4

• Removed parsing Glb code

• Added helper methode GltfVersionChecker.GetGlbVersion(b3dm.GlbData) for checking version of glTF data

• Added b3dm headers FeatureTableJsonByteLength, FeatureTableBinaryByteLength, BatchTableJsonByteLength, batchTableBinaryByteLength.