Autodesk FBX SDK for Unity (com.autodesk.fbx)

When porting functions involving strings:

1. Prefer methods that use const char* over those using FbxString.
2. Note that there is currently no support for out or ref strings. Functions taking char*, FbxString&, or FbxString* require manual scrutiny. Using a const version of these types is acceptable.

The FBX SDK bindings are contained within the FbxSdk namespace. The API structure closely mirrors the original C++ FBX SDK. For example, a static method call like FbxManager::Create() in C++ is accessed as FbxSdk.FbxManager.Create() in C#.

// C++ style
FbxManager::Create();

// C# style
FbxSdk.FbxManager.Create();

Global variables and functions from the FBX SDK are exposed through the Globals class within the FbxSdk namespace. To access a global variable like IOSROOT, use the path FbxSdk.Globals.IOSROOT.

// Accessing a global variable
var root = FbxSdk.Globals.IOSROOT;

Global declarations and macros are placed into a Globals.cs file. In C#, these are accessed via the FbxSdk.Globals namespace.

// Accessing a global variable
FbxSdk.Globals.VarName

All FBX SDK bindings are contained within the Autodesk.Fbx namespace. To use the library in a C# project (such as a Unity plugin), include the using Autodesk.Fbx; directive.

Note that most core objects, such as FbxManager, implement IDisposable and should be wrapped in using blocks to ensure proper resource management and memory cleanup of the underlying native SDK components.

using Autodesk.Fbx;
using UnityEditor;
using UnityEngine;

public class HelloFbx {
  [MenuItem("Fbx/Hello")]
  public static void Hello() {
    using(var manager = FbxManager.Create()) {
      Debug.LogFormat("FBX SDK is version {0}", FbxManager.GetVersion());
    }
  }
}

The C# bindings expose only a subset of the full C++ Autodesk FBX SDK. Users should be aware of the following constraints:

• No Downcasting: You cannot downcast SDK C# objects. For example, if a C++ method returns an FbxDeformer, you cannot cast it to an FbxSkinDeformer in C#. This makes the package unsuitable for building FBX importers.
• Runtime Stability: Performing invalid operations via C# can cause the Unity Editor or standalone application to crash. For example, using an FbxProperty after the parent FbxNode has been deleted leads to undefined behavior.
• Linux Support: Linux support is currently experimental and not officially supported by Unity. If using Linux, you must ensure libstdc++ 6.0.28 or higher is installed.

To run the built-in tests, follow these steps:

1. Create a new 3D project in Unity.
2. Copy the build/install/com.autodesk.fbx folder from your build directory into the Packages folder of your new Unity project.
3. In the Unity Editor, navigate to Window > General > Test Runner to execute the tests.

You can replace a potentially unsafe or complex C++ function with a custom wrapper. This involves ignoring the original function, renaming it to avoid collision, and using %extend to provide a new version with a safer signature that calls the original internally.

/* Example: Replacing a variadic SetCode function to avoid crashes */
%ignore FbxStatus::SetCode(const EStatusCode rhs, const char* pErrorMsg, ...);
%rename("SetCode") FbxStatus::SetCodeNoFormat;

%extend FbxStatus {
  void SetCodeNoFormat(const EStatusCode rhs, const char* pErrorMsg) {
    $self->SetCode(rhs, "%s", pErrorMsg);
  }
}

The Autodesk FBX SDK package can be installed in two ways:

1. Automatic Installation: It is automatically installed as a dependency when you install the FBX Exporter package.
2. Manual Installation: If you need the SDK without the FBX Exporter, you must manually add it to your packages/manifest.json file, as it is not discoverable via the Package Manager UI.

When using an IGNORE_ALL_INCLUDE_SOME strategy, you can selectively expose classes and specific methods to C# using the %rename directive. To unignore a specific method, you must provide the full signature including parameter types and default values.

// Unignore an entire class
%rename("%s") FbxIOBase;

// Unignore a specific method by its full signature
%rename("%s") FbxIOBase::Initialize(const char *pFileName, int pFileFormat=-1, FbxIOSettings* pIOSettings=NULL);

By default, this package is only available for use within the Unity Editor. To use the SDK at runtime in standalone builds (Windows, OSX, or Linux only), you must define a specific scripting symbol:

1. Open Edit > Project Settings in the Unity Editor.
2. Navigate to Player > Other Settings.
3. Under Configuration, locate the Scripting Define Symbols field.
4. Add FBXSDK_RUNTIME to the list of symbols.

To point the build system to a specific local installation of the FBX SDK, modify the FindFBXSDK.cmake file by setting the FBXSDK_INSTALL_PATH variable.

set(FBXSDK_INSTALL_PATH "~/Development/FbxSharp/spike")