HumanoidRetargeter/Core/Formats/Fbx/FbxMeshParts.cs
Utility that parses an FBX token tree to extract names of mesh model parts that can be imported independently. It finds Geometry nodes, follows Connections of type "OO" linking geometries to Models, then returns distinct model names (split and filtered) from Model nodes.
File Access
#nullable enable annotations
using System;
using System.Collections.Generic;
using System.Linq;
namespace HumanoidRetargeter.Core.Formats.Fbx;
/// <summary>Names of mesh instances that ModelDoc can import independently.</summary>
public static class FbxMeshParts
{
public static IReadOnlyList<string> ReadNames(byte[] data)
{
var root = FbxTokenizer.Parse(data);
var objects = root.Child("Objects");
var connections = root.Child("Connections");
if (objects is null || connections is null)
return Array.Empty<string>();
var geometries = objects.Children
.Where(n => n.Name == "Geometry" && n.Properties.Count > 0
&& n.Properties[0] is long or int)
.Select(n => n.Prop<long>(0)).ToHashSet();
var models = connections.ChildrenNamed("C")
.Where(n => n.Properties.Count >= 3 && n.Properties[0] is "OO"
&& n.Properties[1] is long or int && n.Properties[2] is long or int
&& geometries.Contains(n.Prop<long>(1)))
.Select(n => n.Prop<long>(2)).ToHashSet();
return objects.Children
.Where(n => n.Name == "Model" && n.Properties.Count >= 2
&& n.Properties[0] is long or int && n.Properties[1] is string
&& models.Contains(n.Prop<long>(0)))
.Select(n => FbxNode.SplitName(n.Prop<string>(1)).Name)
.Where(n => !string.IsNullOrWhiteSpace(n))
.Distinct(StringComparer.OrdinalIgnoreCase).ToArray();
}
}