Quick start guide - ju1ce/April-Tag-VR-FullBody-Tracker GitHub Wiki

A short guide that will only describe the most important parts of setup. This only describes the bare essentials to get tracking working, you will still have to refine the parameters later to get optimal tracking!

If you get stuck at any step, make sure to read its full tutorial page which should describe it in more detail.

Connecting a camera

The most important part with your camera is that you have manual exposure control! Select which camera you want with the IP/ID of camera parameter. Check the Show preview checkbox, and press Open camera to test the camera.

Dont forget to set Quad decimate as well! Good values are 1 for 480p, 2 for 720p and 3 for 1080p. You will refine this parameter later.

Connecting USB webcam

IP/ID of camera will be a single digit number (0,1,2 etc...). Try a few until Open camera opens the correct camera. Other parameters you want to set is Camera width and height, and FPS. To set exposure, enter 700 into the Camera API preference parameter, and check Show camera settings. This will open another window with camera settings. Set exposure to -8 (or at least -7), and gain to make sure image is bright enough.

Connecting IP webcam

Just enter the IP from the app into the IP/ID of camera. Use a resolution of around 720p and quality of 40-50%, any more will cause delay. To set exposure, use the utilities/set_exposure.bat script.

The trackers

While it is possible to make trackers for 360° tracking, it is recomended to first make 180° version to get a feel for how things work, and upgrade to 360° later.

Print the apriltags_front_475 if you use A4 paper and apriltags_front_450 if you use US letter paper. First row is tracker 0, second 1 and last 2, each containing 2 markers. Make a body for each tracker out of cardboard, which will hold the two markers at a 90° angle. Use something like a rubber band or velcro to fix them to your body.

Make sure that the corner is reinforced and that it stays at a 90° angle, that the trackers are sturdy and dont bend, and that the markers are not covered by anything. Measure the white square of your printed markers and input the measurement into the Marker size parameter.

Calibrating camera

Display the charuco_board on your monitor. Press the Calibrate camera button, and move the camera around slowly while it is pointed towards the calibration board. You want to take images from up close to the board, from steep angles, and you want the dots to be evenly distributed around the image.

Calibrating trackers

First, input the Number of trackers parameter, which is 3 in most setups. Press the Calibrate trackers button, then take images of your trackers. Make sure that the trackers are shaped exactly as they will be when you wear them, if any of your trackers is in two pieces, it has to be assembled during calibration.

Connecting to SteamVR

Use the driver installer inside driver_files to install the driver, then press Connect to SteamVR to connect. If you get an error, make sure the driver is enabled in steamvr settings. If your controllers stop working after this, restarting SteamVR should fix it.

Starting detection

Now you can press Start/Stop to start detection, and the camera feed should open. Put the camera somewhere waist-high, pointed downward, so it will see the trackers well. Put on your headset now. When you stand in front of the camera wearing trackers, the camera feed will show:

• Frame time in top left corner - you want this under 0.033 for real time. If its higher than that, you need to set quad decimate higher.
• All seen markers will have a green outline
• The trackers will have a blue outline. If they leave this outline, they will no longer be detected until they are moved back in.
• RGB axis will show the position after smoothing is applied

Calibrating playspace

To calibrate playspace, first exit SteamVR home. Then check the Calibration mode checkbox. A camera and trackers will appear in your playspace. You want to align the camera with your IRL one, and the trackers with the ones you are wearing.

Pressing left trigger will allow you to move the camera and trackers around. Use it to grab the camera, and move it into the position of your camera IRL.

Pressing left grip will rotate the camera, and move the trackers around the camera. Use it to grab the trackers, and move them into position. Dont use left trigger, as that will cause the camera to no longer be aligned!

When done, uncheck Calibration mode to save the calibration. You are now done, and can begin to use the trackers for FBT in games!

Refining parameters

To get the most out of ATT, you will want to refine the parameters. In the params tab, hovering over a parameter will give you a short description of it. Experiment with diffrent setups, and change one parameter at a time to ensure you can revert in case something breaks!

Multiple cameras

To run multiple cameras, just have two seperate installations of ATT, setup each one seperately, then run them at the same time.