My friend @lobrien (whose blog you should read if you don’t already) was asking about loading Collada files in Scene Kit, so I whipped up a quick example:

SCNScene scene;
SCNView sceneView;
SCNCamera camera;
SCNNode cameraNode;

public override void ViewDidLoad ()
{
	scene = SCNScene.FromFile ("duck", "ColladaModels.scnassets", new SCNSceneLoadingOptions ());

	sceneView = new SCNView (UIScreen.MainScreen.Bounds);
	sceneView.AutoresizingMask = UIViewAutoresizing.All;    
	sceneView.Scene = scene;

	camera = new SCNCamera { XFov = 40, YFov = 40 };
	cameraNode = new SCNNode { Camera = camera, Position = new SCNVector3 (0, 0, 40) };
	scene.RootNode.AddChildNode (cameraNode);

	View.AddSubview (sceneView);
}	

In the Xamarin Studio solution pad, the folder containing the Collada file has a .scnassets suffix, and the model has a build action of SceneKitAsset:

Given this, the model is rendered as shown below:

There’s also a Collada build action as well. I’ve never used that option though. If someone wants to elaborate on what that does (perhaps supporting animations embedded in Collada files? just a guess) please add a comment here.