The base station can track multiple Trackers, so there can be more than one Tracker in the scene.
Below, from right to left:
Position 1: LED indicator, used to indicate the status of the Tracker, same as the joystick, if the blue light is blinking, it means that the device is not yet paired; if the green light is on, it is starting to work and normal; If the red light, it means the power is low.
Position 2: Device Switch.
Position 3: Similar to the handle, the sensor used to receive the signal from the base station.
Position 4.1: 1/4 inch screw hole to attach it to a standard tripod head, same as DSLR.
Location 4.2: Pin slots for added stabilization.
Position 4.3: Spring loaded pin, 6 positions.
Position 5: USB port, used on the one hand for charging and on the other hand for communication with the PC, such as updating firmware.
Regarding the 6-position spring-loaded pins in position 4.3, players can communicate with them by creating their own peripherals such as electrical switches and sending electrical signals to achieve the effect of sending key triggering events to the PC like a joystick. The following figure shows the names of the key signals corresponding to each of the 6 pin positions. It's really a neutered version of the joystick, or rather, a keyboard with no buttons and only keyswitches.
Tracker has a lot of application scenarios, the first one is more commonly used is tracking objects, you can bind it to some objects, such as bats, rackets, clubs, seats, etc. In the traditional industry, it can be bound to some maintenance tools, wrenches, hammers, etc., so as to achieve a more realistic experience.
In addition, we know that Tracker has spring-loaded pins and USB ports, and can also make some peripherals that meet specific usage occasions to be more in line with the peripheral's usage habits. For example, the PPGun, which is more typical now, communicates through USB ports, mapping the original handle's buttons to the gun body's relevant functional parts, such as the Trigger key corresponding to the gun's trigger. Touchpad is mapped to the gun's joystick, etc.
In addition, Tracker can be used as a motion capture device. As we know, with the existing VR devices, only handle and helmet, it is difficult to realize the whole body motion capture, so using Tracker, with some reverse dynamics plug-ins, such as FINAL-IK, we can realize the whole body motion capture in VR. The base station can track multiple Tracker devices, so it's possible to bind multiple devices to key parts of the person, such as the feet, knees, waist, etc. The more devices there are, the more accurate the captured motion will be.
Tracker package contains a wireless receiver, when you need to use the Tracker while using the handle, then you need to connect this wireless receiver to the PC, used to receive signals from the Trakcer, in the use of the two handles need to be turned on at the same time; if you do not use the wireless receiver, the system will be Trakcer is considered to be a controller like the handle. controller.
The first time you use Tracker, you need to pair the device, when you press the switch, the blue light will flash, indicating that the device is waiting for pairing, right-click in the SteamVR Runtime (note that this is the SteamVR Runtime, and we've differentiated between the SteamVR SDK and the SteamVR Runtime in previous lessons) and select "Devices" - "Pair Controllers" to complete the pairing. After successful pairing, you can see the icon representing the Tracker, as shown below.
As a developer, the most important thing is how to use Tracker inside the engine, we take Unity as an example, the development of Tracker doesn't need additional SDK support, you just need to import the necessary VR development in SteamVR SDK. In SteamVR, all objects that can be tracked by the base station are considered Tracked Objects.
1. You need a visual object in the scene to mark the Tracker, in the engine, you can create a new GameObject to mark the Tracker, name it Tracker, and add the SteamVR_TrackedObject script to it. TrackedObject script.
After adding the TrackedObject script, you can specify the VR device corresponding to the tracked object in the drop-down list, which defaults to HMD, i.e., helmet, and Device1 and Device2 correspond to two grips, and so on. (Note: you can leave the assignment alone here)
2. Add a visual 3D object to the Tracker container, in this case a Cube.
3. Select CameraRig, and in the Objects property of the Steam VR_Controller Manager, add the Tracker to the array element in the Steam VR_Controller Manager's Objects property.
4. Click Play and you can see that the Cube identifies the Tracker's position and orientation.
Now that we have identified the location of the Tracker, we can add a model to the scene that is mapped to the same model as the real world. We've described customizing the joystick as a virtual prop before, so using the Tracker to bring real objects into VR will give us a more realistic feel, first of all don't make me think that the user doesn't need to know about the real thing. First of all, don't make me think, the user does not need to understand how to use the props, how to use the buttons of the handle, just need to follow the natural way of use. The second is to be able to get the same sense of real operation as reality.
Due to the lack of realistic props, I mapped the tripod to a spear.
1. Delete the added Cube and drag the prepared spear model into the scene as a child of the Traker container.
2. Add visual nodes to the Tracer container.
3. Adjust the relative positions of the props and the Tracker container. I placed the Tracker at the top of the tripod head, so it needs to be kept in this position in the scene, as shown below.
4. Adjust the orientation of the props, rotate 90 degrees, position and orientation, according to the model coordinates and specific application scene adjustment.
5. Click Play to test, when moving the tripod, the props in the scene changed accordingly.
Above is the basic use of Tracker, the subsequent development of Tracker is not too much related to the basic development of VR can be merged into the line. Tracker single function, there is not too much deep black technology in it, the development of its development, there is not too much new knowledge, so the limitations on the function of its just imagination, you can According to their own VR application scenarios, give full play to the imagination, in order to develop more creative content.