[MUSIC] By now you should have had a good overview of how VR display works and how it supports immersion. In this video, we will move on to another component of VR hardware, the VR controllers. Again, let's start with the cave. What this user is holding in their hands is something called a VR controller, or we often refer to it as the wand. In VR, you will be interacting with objects using these wands, picking up and moving objects, or when you're talking with a friend pointing at something, or gesturing. In order to pick up an object in the 3D space, the system will need to know where your hands are. So we will need to be able to track the position of the wand. In the real world, if I like to grab my mug to see if I still have tea in it, I will have to rotate the mug slightly. So in VR, I should also be able to do this, which requires rotation tracking of the wand. The same thing applies to communication functions. If both the position and rotation of my hands are tracked, so with a wand, I will be able to use gestures to communicate to some extent. So essentially, we need to track the position and rotation of the wand. This is done exactly the same way as hat tracking. The wand itself has a built-in system to track rotation and it uses external optical sensors to track it's position. Other than interacting with objects and gesturing with friends, often the wand is used for something we don't normally do with our hands in real life. That is navigation. Basically, we can use the wand to walk around 3D world without moving the actual position of our body. This enables users to explore a virtual world that is bigger than the physical space they're actually in. The methods for navigating the 3D world without having to move your body often come from our experiences in video games with a 2D user interface. In order to look and move around in a video game, we often use a touchpad, mouse, keyboard, or joystick. A similar method has been adapted for us to navigate in VR. As you can see in the middle of the wand, there is a small joystick which you can use to navigate your 3D environment. When you use the joystick to move around in VR, it can be called virtual navigation, as opposed to actually moving around in the physical navigation of the real life. But there are many other ways in which you can use a wand to navigate in VR without using this joystick. And these methods are often more natural and less likely to cause nausea. We will talk about these navigation methods and nausea in VR later in this course and the other courses in our VR specialization. The VR controllers used in high end HMDs are very similar to the ones used in the cave. They're both rotation and position tracked. And they often come with a joystick or touchpad in the middle for navigation. Furthermore, most VR controllers nowadays are able to provide haptic feedback through vibration. So, what does this haptic feedback through vibration mean? In real life, when I put this mug on the table I will feel a small vibration the moment the mug touches the table. This can be supported by the controller in VR. Because we have the position tracking of the wand, the system knows where the mug is moving in a 3D space, and it knows the 3D position of the table. So when these two overlap with each other in the 3D space, at the moment the mug touches the table, the system can detect it and make the controller generate a small vibration to resonate with what I expect to feel in real life. This gives a very strong sense of immersion. This illusion is so strong, I have seen various cases of people who after spending some time in VR, putting virtual objects on a table that doesn't really exist, were so convinced subconsciously that there was a table, they would lean against it and fall. For myself, there were a few times I almost left the VR controllers on the virtual table because I forgot that it didn't really exist. Fortunately, I have never dropped and broken one so far. Another point I would like to mention is that when our uses try to move around using the joystick and touchpad, which is something we call virtual navigation, it's more likely someone would feel nausea in the HMDs than in the cave. So you are encouraged to find other ways to navigate the 3D space rather than just importing a first person controller normally designed for a 2D user interface. Again, we will talk more about this later in this course. Finally, when it comes to mobile VR systems, only some of them come with a controller. But the position of the controller is not normally tracked for the same reason we discussed with hat tracking. Also, they don't usually have built-in mechanisms to provide vibration feedback. Google Daydream comes with a controller, with a touchpad which provides rotation tracking. Samsung Gear VR hs a touchpad on the right hand side of the HMD. [MUSIC]
