Getting started with motion controllers

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What's this for

Wanna capture hand/prop movements? Now this is possible with the support for motion controllers added to iPi Recorder. Essentially, motion controller provides one 3D orientation value which can be used to track rotations of a single bone, whether it is a body part or attached prop.

Equipment

PlayStation Move

Wii Remote with MotionPlus

Now, what you need to try this. First, a motion controller (or several ones, iPi Recorder currently has no limitation on the number of controllers). Two models are supported, both of them are easy to buy:

• PlayStation Move
• Wii Remote with MotionPlus
• Wii Remote Plus, which has MotionPlus integrated

Important. If you don't already have Wii stuff, we strongly recommend to use PlayStation Move, because of its built-in magnetometer. In short, the presence of magnetometer gives a lot more stable orientation value. Without it, orientation tends to drift around vertical axis, and this leads to less accurate measurements.

Also, your PC should be equipped with a Bluetooth radio module to connect with motion controllers. If you do not have a built-in one, you'll need an USB Bluetooth adapter (like this one). You'll need only one Bluetooth adapter for any reasonable number of motion controllers (at least 4). For PS Move, you will definitely need an USB to mini-USB cable to charge your motion controller and for pairing (see next section).

Getting into Recorder

The big change is that Cameras stage in iPi Recorder was renamed to Devices, because now it may contain not only cameras.

To get your motion controller in the list of devices, it must be connected to a PC via Bluetooth. But before it can connect to your Bluetooth adapter, the controller must be paired with it. That is where button ADD NEW helps. So, your first step is to press this button, select device type you have, and then follow the instructions specific for this device.

Note. For PS Move, pairing is one-time process unless you reconnect motion controller to another PC or gaming console. Each time you connect controller to another host, it should be paired. After pairing, the Bluetooth connection is established automatically each time you power on the motion controller. For Wii Remote, pairing should be done each time after Bluetooth connection is lost, either powering off the motion controller or the PC. This is another disadvantage of Wii Remote.

After you have successfully paired the controller with Bluetooth adapter, it should be visible in device list. Mark it selected and go to Setup stage. Here for the first time you will see the controller visualized as a rotating blue "brick". And also you should see a message over it saying it is not calibrated. Calibration of a motion controller (not confuse with calibration of cameras) is needed for more accurate measurements, so it is highly recommended to get through it every time you see this message. To run calibration process, press CALIBRATION button in on-screen controls.

Device list

Motion controller visualization. Controller is not calibrated.

After a motion controller is calibrated, you can use it in recording action videos.

Tip. There is no need to enable motion controllers when recording calibration videos, because their data will not be used in the calibration process.

Tip. Under certain conditions (generally indoors with dim lighting), PS Move's light sphere can be used as a light marker for calibration. Here is short instruction:

• Ensure PS Move is visible in device list.
• Unselect it, when going to Setup stage.
• To change the color of the sphere, press button combination on the controller:
  • Select + Move — White     
  • Select + Cross — Blue     
  • Select + Square — Magenta     
  • Select + Triangle — Green     
  • Select + Circle — Red     
  • Select + T (Trigger) — Cyan     
  • Select + Start — Yellow     
  • Select + PS — Off     
• Proceed as usual with recording a calibration video. Do not change the color of the sphere during recording.

Tips on action video

The main thing is that in T-pose, hand(s) holding motion controller(s) should have zero rotation to get default orientation of controller.

Sorry guys, this was the wrong main thing :-/ After conducting some experiments while implementing motion controller support in Studio, we've come to the real two main things (requirements):

1. At some moment during the record (for example, at the beginning), you should aim with (each) motion controller at one of the cameras. It is needed to correctly orient the motion controller within the scene coordinate space in iPi Mocap Studio.
2. For correct orientation of prop models in iPi Mocap Studio, hold the controller as if its side with buttons is a back side of a prop in a "standard" position — i.e. facing the actor's face when the arm with prop is stretched forward. Of course, you can use a non-"standard" grip of the controller if such a grip for a prop is implied by the scenario of the action.

Now, the tips:

• If you have already made some records without explicitly aiming at the camera, these videos may not be going to trash. Look thoroughly through all the frames — it is very likely that at some point the actor aimed at some camera by accident, at least in horizontal direction (this is sufficient).
• You can use special accessories for motion controllers like shooting attachments. In that case, the relative position of the controller to the prop is good known, so you just hold it as needed by the scenario (i.e. the requirement #2 is not relevant for this case).
• You can change the grip of the motion controller during the action. The iPi Mocap Studio allows you to process every frame range with the same grip independently.

Tracking

After all, the sad news :( iPi Mocap Studio is not yet capable of using motion controller data for tracking. The update will be published in 2-3 weeks (this has been written on Nov 03, 2012). Use this time to get required stuff and make some test records!