Each plug-in type exposes its functionality to 3ds Max by defining a class that derives from a specific base-class and providing implementations of key virtual functions. The most important base class is Animatable, which most plug-ins implement from.
The following is a list of the most important plug-in types and the base classes they derive from:
Tex3D.Control.Atmospheric.BitmapTex.GenCamera.ColPick.IBoolObject.BaseBehavior.SceneExport.SceneImport.GeomObject or SimpleObject2.GUP.IDX9DataBridge.ImageFilter.BitmapIO.ViewFile.IKSolver.ConstObject or HelperObject.LightObject or GenLight.LinearShape.Manipulator or SimpleManipulator.Mtl.MSPlugin.Modifier or SimpleMod.IMultiPassCameraEffect.ParticleObject or SimpleParticle.PatchObject.RadiosityEffect.Renderer.Effect.IRenderElement.Sampler.Shader.ShapeObject.Osnap.SoundObj.SimpleSpline.SpringSys.Texmap.TrackViewUtility.UtilityObj.WSModifier.