[MUSIC] With hypernatural interaction techniques, you can extend your arm to reach out for things further away from your arm's length. But it still uses the metaphor of how we interact with objects by grabbing them with our hands. In the real world, we also indicate objects of interest by pointing at them. And in real life, when I really want to be precise and clear when pointing at something, for instance when I give a presentation, I might use a laser pointer. Magic interaction uses this metaphor for object interaction. And it's often referred to as recasting of virtual pointer. So with this method, I'll be holding a controller which acts as the laser pointer. I can use it to indicate my object of interest similar to the previous methods, and we need some way to confirm my selection by clicking a button, and hopefully, also receive some system feedback in the form of color, sound, or vibration. In terms of object selection, I will need a controller to be tracked with at least two degree of freedom. That is pitch and yaw. In some situations, it will also beneficial to have another three degree of freedom, precision tracking, so in total we have five degree of freedom. This is in particular useful in a cluttered environment where you have objects blocking each other. For instance, in this diagram, if the user's controller is not position tracked, it would be impossible to select object A. In terms of object manipulation including changing the position, orientation, and scale of the object, it is also useful to have five or six degree of freedom instead of just two. But without six degree of freedom, it can be still quite difficult to manipulate objects out of reach with a pointer. In real life, although we often indicate objects out of reach with our hands or a pointer, we don't usually manipulate objects out of reach. So we don't really have a real-life metaphor for this. It is just not something we do in real life. So it would be also difficult to do in VR. In fact, although the virtual pointer metaphor could sometimes even outperform the simple virtual hand or the hypernatural metaphors, in terms of object selection, when it comes to object manipulation, natural or hypernatural methods have always been the more effective way. Most of us just find it really awkward and unnatural to manipulate an object with a pointer. So although it might break the plausibility elution, but if in your application, you're really keen to improve user performance in selection and manipulation of objects out of reach, you can try a hybrid method by combining the simple virtual hand with the virtual pointer. For instance, you can use a virtual pointer to select an object. Once the selection is confirmed, you can switch to the virtual hand metaphor by having this object attached to your virtual hand. You can then manipulate the object naturally with your hands by changing its orientation or scale. Once this is done, you can switch back to the virtual pointer metaphor, to select a position where you want to put this object back to. So using a tracked controller for object selection uses the virtual pointer metaphor. And it's normally referred to as ray casting. If you don't have a controller with your VR system, you can also do ray casting from your head, which is either three or six degree of freedom tracked. So you can be looking at a object to select it, or you can use a combination of your head and controllers. If both the head and controllers are position tracked, we can hold the controller in front of our head and imagine a virtual ray, which shoots from my head, going through the controllers in a straight line to the object you want to select. This method is called occlusion or framing. Or we can have the ray coming from our head, but instead of defining another position for the ray to go through with our controllers, we can control orientation of the ray with the rotation of our controllers. This method and the occlusion method can be useful in case of eye-hand visibility mismatch, where it would be tricky for the user to select certain objects otherwise. One other method for object selection and manipulation by giving you magical power is called World In Miniature, or WIM. Basically, this gives you a miniature model of the virtual world, which you can hold in your hand and manipulate. Objects in the big virtual world will update according to your manipulation of the downscaled model. The same method can also be used in navigation. For instance, in teleporting, you can indicate in the miniature world the position you would like to be teleported to. So that's a lot of super powers you can have in VR in terms of object interaction. Of course, there are many other creative ways you can interact with objects in VR. Important thing here is about finding the correct method for your application that will make the users happy. [MUSIC]
