Prepare for Motion Capture

Notch is the premiere motion capture system for smartphones to support 18 and more sensors. Notch is the first motion capture product to offer SDK that enables creation of consumer-facing motion analysis applications.

Workflow

Follow these simple steps to prepare for the capture:

  1. Choose Your Configuration
  2. Calibrate Your Notches
  3. Wear Notches
  4. Steady Your Avatar

1. Choose Your Configuration

Configurations can be found under the Capture menu item. They

  • give quick access to capture the motion of the desired body part group (Upper Body) in a given sensor-settings (@100Hz sampling frequency).
  • also serve as the grouping convention for your recorded motions (Library).

You can choose from existing configurations (Full body, upper body, lower body, right arm etc) and you can also create your own, which is discussed in the next chapter.

2. Calibrate Your Notches

During the calibration, the nothces’ magnetic sensors are tuned for the magentic environmental. For optimal performance, you should calibrate the notches at the very beginning of a recording session or if you think your notches may got magnetized.

This is how you calibrate:

  1. Place all the notches into their slots in the dock and close the dock lid.
  2. Tap the “calibrate” button (left menu).
  3. Rotate the dock following the onscreen instructions in the app.

Good to know If you think your notches get magnetized, (you receive lots of magnetic warnings during capture), then we suggest you calibrate only three (3) notches at a time, placing the devices in the three corners of the dock.

3. Wear Notches

Put on the straps and place the notches into their mounts on the straps according to the color scheme. Place notches into the mounts with the white side facing outward.

Our recommendations:

  • Securly attach the Notches, and make sure they do not move (or shake) during the activity.
  • For optimal performance, place the notches on the body where you experience the least tissue movement.
  • Avoid any metal objects near by. Make sure no metal pins, buckles, phones are in the close distant (e.g. within 5-10cm, depending the size of the metal object). Do not ever put any permanent magnet close to the notch.
Body Part Location
ChestTop Few cm-s below the breast, facing front, wear it as a heart-rate monitor
Hip The device on the hips needs to be on Hip-joint level. You may visually observe as you ask the user to bend forward. Either keep it on the front, or place it to the sides.
UpperArm 5-10cm above the elbow, on the side
Forearm (wrist) On the wrist, wear it as a watch
Thighs 5-10cm above the knee, facing front
Lower Leg 5-10cm below the knee, facing front
Head Half-way between the front and side

Good to know To link the user’s 360deg heading to the virtual avatar’s, a dedicated notch’s orientation needs to be referenced. This bone is called the “reference bone” and by default set as ChestBottom - Front. This means the device on the ChestBottom needs to face forward. If you create a configuration without the ChestBottom, you will need to choose a reference bone and assign a directionality. For example, if you measure the Right Arm with 2 bones, choose the RighUpperarm as a reference bone, with a direction: facing right. Make sure the user wears the notch on the Right UpperArm facing right.

4. Steady Your Avatar

During the Steady pose the notches will memorize their orientation so that it is matched to the predefined skeleton pose. It is important that you follow instructions for the steady pose as close as possible.

The steady pose only takes a few seconds. Tap “steady” in the app and mimic the posture of the avatar: stand straight, keeping legs at hip-width, toes pointing forward, and arms stretching along your body. The app will notify you when the steady pose is analyzed.

Steady
Steady

Good to know You can skip the steady. When using this feature, the steady pose is taken from the first second of any capture. The 3D capture needs to start from the steady pose. We recommend using this feature in more dynamic activities where the straps may move between sessions, e.g. high jumping.


Getting Started
Motion Capture Settings