How to create a 3D stroke animation with Maya and ARKit

Shout out to Mark Yagos for the guidance.

Part One: Create the stroke animation in Maya

Please note that this tutorial is only for a two-joint animation.

Step One: Create a straight bezier curve

Step Two: Add a NURBS circle and adjust it to an edge of the curve

Step Three: Extrude the cylinder

Step Four: Add joints to the start and end of the cylinder

Step Five: Bind the joints to the surface extrude by selecting both the joints and extrudeSurface1 and doing the following

Step 6: Implement the Animation by pressing S at the correct keyframes and changing the ScaleX of the Joint1.

Step 7: Export the animation as a Dae

Remember to change the bake animation end to the right keyframe.

Important export functionality

Part Two: Implement in XCode

Add your scene to XCode as demonstrated in this tutorial and then use the code below.

Biggest lesson from this adventure was that to use a joint-animation you must add both the geometry and the joints to the scene, in order to be able to run the animation.

let scn:SCNScene? = SCNScene(named: YOUR_SCENE);
for child in scn!.rootNode.childNodes {
node.addChildNode(child)
}

scn?.rootNode.enumerateHierarchy({ (child, _) in
print("Child : ", child);
for key in child.animationKeys {
print("KEY : ", key);
let animation = child.animationPlayer(forKey: key)?.animation;
animation?.repeatCount = CGFloat(HUGE);
animation?.isRemovedOnCompletion = false;
self.sceneView.scene.rootNode.addAnimation(animation!, forKey: key);
print(animation!)
}
})

Oscar