FBX SDK Programmer's Guide > Animation > Animation data structures >

# Writing and using your own evaluator

Class FbxAnimEvaluator is the class to use when you need to evaluate the animation in a scene:

    // Let’s assume that myScene has been created already
    FbxAnimEvaluator* mySceneEvaluator = MyScene->GetEvaluator();

But FbxAnimEvaluator is actually an abstract class. When you call FbxScene::GetEvaluator in the above code snippet, the function actually creates a FbxAnimEvalClassic object. FbxAnimEvalClassic is the only implementation of FbxAnimEvaluator in this release of FBX SDK.

You can, however, implement your own evaluator class derived from FbxAnimEvaluator. To use your evaluator class, call FbxScene::SetEvaluator, setting the evaluator to your own evaluator object. Then, make this call, which is exactly the same call that you see in the above code snippet:

    FbxAnimEvaluator* mySceneEvaluator = MyScene->GetEvaluator();

This time, mySceneEvaluator will point to an object of your own evaluator class.