Put axes on floor [get photos]

By Jamie Arnold,2014-01-20 03:08
19 views 0
Put axes on floor [get photos]

    Zoom’s Guide

    to MoCap

    Bo Daly






Know the Lab.

There are five (5) machines in the MoCap studio. The leftmost computer, “Waltz,”

    is the machine that you will use to do all of the Motion Capture and cleanup work.

Next to Waltz is the Vicon capture machine, which must be networked to Waltz

    for anything to work.

     The white box here is the Vicon machine. it’s a good box, but can be a little tempermental. If it

    gives you any trouble, turn it off and on with the switch on the lower right.


Next to the Vicon machine is an SGI.

To the right of the SGI, on the other table, is a large black box, the MotionStar

    machine, which is used to process data from the magnetic tracking system in the


To the right of the MotionStar box, past the A/V equipment, is a monitor that is

    used for both the realtime server, “Rumba” (the black Dell on the floor) and the

    realtime playback machine, “Muybridge.hcii”, which is running alice.

    Say hello to Russ if you see him down there. He gets lonely sometimes…


Know the Software.

On Waltz, you will find a desktop shortcut to a program called Workstation. This

    is the program that you will use to record motion and to build a skeleton from the

    MoCap data.

    You will also find a shortcut to Bodybuilder. This tool will be used later to clean

    up the data that you’ve recorded.

To begin Capturing Motion, run Workstation.


From the File Menu, Open the ETC MoCap Database:

    File->Open Database->ETC

This, of course assumes that you’re in the ETC. Otherwise, you may want to

    make a new database somehow.

That’s it for the preliminaries. Now you’re ready to get calibrated and get jiggy.


STEP I: Calibration

The first time you enter the MoCap Studio in WH1328, you will have to calibrate

    the Vicon Motion Capture System to ensure precise measurements. After initially

    calibrating the system, you should be able to use it without recalibration, provided

    the cameras are not moved in the studio.

Place the Static Calibration Axes on the floor as shown in the picture. In the

    center of the performance space, there is a large, blue, asterisk-shaped marking

    on the floor. Near this marking are two markings at right angles. Align the Axes

    approximately with these markings.

This isn’t really a precise science. Just get the axes near the center of the

    capture space, which is delimited by blue markings on the floor.


    The first order of business is to ensure that all of the cameras can see the axes. Click on Camera Icon (the 5th button from the left) to bring up Live Monitor.

    Click the arrow buttons in the lower left to cycle through all of the cameras, making sure all 12 cameras can see axes..

    If all is well, close the LiveMonitor. If all is not well, you may have to re-aim the cameras or clear all lines of sight to the axes. Reaiming the cameras is beyond the scope of this document. You should never have to do this, and should not attempt it without parental supervision.


     thPress the “Calibrate Button” – the 6 button from left on the toolbar

The calibration process involves a static calibration and a dynamic calibration

    step. To begin calibration, press the “Calibrate” button.

Press start button to start the static calibration.

    After approx. 3 seconds, the calibration should automatically stop. If it takes

    substantially longer (10 sec or more) or says “initializing”, you will have to hard

    boot the Vicon machine and restart the Workstation program to try again.


    After the static calibration phase, remove the axes from the stage, and take out the calibration wand.

    This is the dynamic calibration wand (in the clear space capsule). It lives near all of the other markers behind the magic black curtain. Remember to close the curtain before capturing, as the reflections form the objects inside will screw up your data.

    This, by the way, is the reason why we aren’t allowed to wear shoes in the lab. Aside from possibly damaging the special squishy floor, many shoes have highly reflective materials that reflect the IR light from the cameras.


Press start button again to begin the dynamic calibration step.

    Walk around the stage area and wave wand around. Workstation will display a

    count of the number of frames taken. Go about 400 frames, or until you’ve covered entire space, and then press the stop button.

Be sure to spend a good amount of the time waving the wand near the corners of

    the space. The lower bound is the floor, and the upper bound is a little higher

    than head level. You still have to do the other areas, but the corners require a

    little more attention.


Report this document

For any questions or suggestions please email