Vicon Motion Capture Quick Guide

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Table Of Contents

Preparing the System1.

Powering on the systema.

Calibration and Configuration2.

Connectinga.

Setting Framerateb.

Adjusting Camera Settingsc.

Setting Camera Thresholdsd.

Calibrating Camera Positionse.

Setting the Originf.

Suiting up3.

Putting on the suita.

Marker Placementb.

Preparing Subject & Capturing4.

Setting up the Databasea.

Calibration Capture Trialb.

Subject Calibrationc.

Capturingd.

Exporting the Datae.

Getting Data Into Lightwave5.

Lightwave Exporta.

MotionBuilderb.

The Maya Hackc.

Lightwave Importd.

Clean up after yourself6.

System Operator's Section7.

1. Preparing the System

Take off the lens caps if they are still on. You can use a chair with no wheels to stand on to reach the lens caps so that you can

remove them. Try not to move the tripod as that will change the viewing volume. Also, take care not to rotate the lens, as it will

change the focus.

Hide all reflective materials from view of the camera. Anytime you handle markers or other reflective materials, you should

make certain that you did not leave any unnecessary reflective materials in sight of the cameras.

a. Powering on the system

Power on the cameras using the switch on the back of the box labeled VICON MXULTRANET.

on Motion Capture Quick Guide http://www.cacs.louisiana.edu/labs/ecrg/vicon/

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VICON MXULTRANET

The Power Switch

2. Calibration and Configuration

a. Connecting

Start Vicon IQ. There should be an Icon.

Press the Setup button at the top and then open the Hardware Config tab from the left sidebar. You should wait for the squares

next to each camera to turn dark green before moving on. If one of the 8 cameras does not show up in this list after some time

press reboot all. Later, if a camera fails to produce an image, we can use open this panel and choose the camera that is giving us

problems, then press the reboot button to get the camera working again.


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Hardware Configuration

Now we are ready to connect by pressing the the connect button.

If IQ crashes, restart and try to connect again, also hit ok when any dialog box appears

Now all the squares in front of the cameras turn bright green.


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Connection Established

b. Setting Framerate

Once You are connected, go to Sync Setup on the right sidebar, also under Setup. A panel will open that allows you to adjust the

framerate. You should set the framerate to 120. This will allow faster calbration and less eyestrain.


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Adjusting Frame Rate

c. Adjusting Camera Settings

Next you need to adjust the cameras' settings. Open the camera settings panel on the right sidebar. Also, from the top of the

screen, switch the view to the camera view.

You must first select all the cameras in the list that you want to adjust. For simplicity, you may just want to use these suggested

values:

Strobe Intensity: 100

Camera Threshold: 40

Gain: 1

Circle Quality: 30

Strobe intensity is the brightness of the red LEDs. You usually want to put this all of the way up because it poses no risk of

damaging the LEDs and allows the cameras to better differentiate markers from the background.

Camera Threshold is the threshold of brightness at which the cameras will recognize as object as a marker. We may need to raise

this if we get closer to the cameras, or objects in the room are especially light and reflective. If we can't see the markers we mayneed to lower it.

Gain is digital amplification of the camera input. You always want this as low as possible.

Circle Quaility determines how perfect a shape must be to be recognized as a marker. Due to concerns such as lens distortion,


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we should keep this relatively low. Raising it can help avoid recognizing reflections from an object as a marker

Camera Settings

d. Setting Camera Thresholds

Next we need to ensure the thresholds are set correctly. This step usually will not need to be taken if the camera have not

moved since the last time thresholds were set.

Thresholds are used to ignore certain regions of each camera. This allows us to block out reflections or the strobe of another

camera.

First make certain all reflective objects, espcially markers are hidden from view of the cameras. Open the Thresholds panel from

the right sidebar. Also switch to camera view. If you see anything on any of the camera views, first make sure it is not a marker

or reflective object that can be moved. If the cameras can still see something press "Start Recording Background" wait a bit,


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then press "Stop Recording Background" and "Save Thresholds And Apply". If you didn't see anything in the cameras, the old

thresholds must still be good.

About to set thresholds

Now you should not see anything in the camera views.


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Thresholds now set

e. Calibrating Camera Positions

Now we need to open the calibration kit to start the calibration.


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The Calibration Kit

Open the Calibration Kit and take out the 240mm Wand. (It is labelled.)

Calibration Kit Contents: 240mm Wand, 14mm L-Frame

At this point you should stand in the center of the capture volume (marked with tape) with the wand and look at the camera

views to make sure they can see the markers. You can switch to a view that allows you to see all the cameras at once to help you

do this faster. If one of the cameras cannot see the wand, you will need to go back to the Hardware Config panel under Setup to

reboot that camera.

Now, at the top of the screen press the Calibrate button. Open the calibrate sidebar on the right if it is not already open. UnderCalibrate cameras, make sure "240_mm_Wand" is selected from the drop down menu. Choose full calibration and click start

wand wave.


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Starting the Calibration

During the wand wave a person needs to walk around the capture volume and wave the 240mm wand. You should see all of the

cameras being painted with a rainbow-like pattern that indicates where the camera has seen the wand. You will want to make

sure all of the camera views become densely coated with this pattern. Also, you will see a status report that tells how many

wand points each camera has seen. You should not stop until all of the numbers turn green. (about 10,000 points per camera)


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Wand Wave in Progress

A good calibration should result in mostly goods and some excellents in the Status Report. Note that the error is measured in

pixels, so the error is relative to the distance from the cameras.


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Typical Calibration Results

f. Setting the Origin

Next we need to set the origin. This will be the position and direction of X, Y, and Z axes to be used when recording

mocap data.

The first step in setting the origin is to remove the 14mm L-frame from the calibration kit and set it in the middle of the capture

volume or wherever you want the origin to be. Two metal plates pivot open to reveal two bubble levels. You can use the knobs

on the L-frame to level these, then close the metal plates.


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L-Frame: Adjustment Knobs inRed

If you have not done so already, at the top of the screen press the Calibrate button and open the calibrate sidebar on the right.

You should also switch to the Live 3D Workspace view from the bar across the top.

You should notice that Camera 1 is the origin, we need to change this.


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Cameras with Arbitraty Origin

Make sure "Ergo_14mm_LFrame" is selected under "2. Set Volume Origin And Axes". Then press Track L-Frame. You should

see some dots in Live 3D Workspace showing where the L-Frame is located. Now press Set Origin. The cameras in Live 3D

Workspace should now be centered in a ring about the origin.


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Cameras with Origin Set

You should do some quick testing before you move on. Take the wand into the center of the capture volume and look at the Live

3D Workspace to see if you can see 3 small points. You should also get familiar with the view controls.

View Controls

ALT + Left Mouse Rotate

ALT + Right Mouse Zoom

ALT + Left Mouse + Right Mouse Pan

3. Suiting up

a. Putting on the suit

There are 4 sizes to choose from for the suit: Small, Medium, Large, and Extra Large. You Should pick the smallest suit you can

wear that does not constrict your movement. Remember that the purpose of the suit is not just to allow you to put markers all

over your body, but also to keep the markers from moving.

Next you should use velcro straps to attach the top and bottom of the suit and also to tighten any loose areas such as the back of

the knee.


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If you have long hair you should tie it up in a polytail, otherwise it may obscure markers on your back.

b. Marker Placement

Before placing any markers, we must decide which skeleton template we will use. The skeleton template describes the bone

structures, how many markers to use, and how those markers relate to the bone structure. For this example we will use the

skeleton template located at "C:\Program Files\Vicon\Models\ViconiQ 2.5\iQ_ACTORExample_V5.vst".

Press the Modeling button at the top, then from the File menu use Open to open the skeleton template you want to use.

You should now be able to view your skeleton using the rotation panning and zoom commands you learned earlier. Each of the

sphere with a yellow line that extends back to a bone represents a marker. Now use this guide to place markers on your body

where needed.

Viewing Skeleton Template

It is very important to note that marker placement is relative, not absolute. You do not need to match the diagram exactly, as

long as each marker is somewhere on the same bone as in the diagram. For example, in this diagram we have a marker on the

top of the head, but since we only have a headband to put markers on, we can just place it on the back of the headband as it is

still on the head.

Avoid placing markers on muscles as they will cause the markers to move independently from the bones. Whenever placing at a


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rotation point you should rotate your joint and try to find a point that rotates the least, preferably on a bone, and place it there.

Markers are usually placed on the outside of joints so that they will be more visible to the cameras. It is also suggested to make

your marker setup asymmetrical to help Vicon IQ tell your left from right.

iQ_ACTORExample_V5.vst contains the following 47 markers:

5 Head

LFHD: left front head

RFHD: right front head

LBHD: left back head

RBHD: right back headARIEL: top of the head

4 Shoulders

LFTShould: left front shoulder (clavicle)

RFTShould: right front shoulder (clavicle)

LSHO: top of left shoulder (place on bone)

RSHO: top of right shoulder (place on bone)

4 Upper Arms

LUPA: middle of left upper arm (not on muscle)

LELB: left elbow (find the part of the bone that does not rotate)

RUPA: middle of right upper arm (not on muscle)

RELB: right elbow (find the part of the bone that does not rotate)

4 Lower Arms

LFRM: left forearm (place directly on ulna)

LWRIST: top of left wrist just before rotation pointRFRM: right forearm (place directly on ulna)

RWRIST: top of right wrist just before rotation point

4 Hands

LTHUMB: base of left thumb

LPINKY: base of left pinky

RTHUMB: base of right thumb

RPINKY: base of right pinky

5 Upper Back

TopSpine: top of the spine

MidBack: on spine where the ribcage ends

STRN: centered on sternum

LRRShould: left shoulder blade

RRRShould: right shoulder blade

7 Lower Back / Pelvis

Root: the base of the spine

LFWT: left front waist

RFWT: right front waist

LBWT: left back waist

RBWT: right back waist

Pelvis: just above the waist, skewed to one side

LowerBack: just below the middle of the back, skewed to one side

4 Upper Legs

LTHI: outside middle of left thigh

LKNE: outside of left knee

RTHI: outside middle of right thigh

RKNE: outside of right knee

4 Lower Legs

LSHIN: left shinLANK: left ankle

RSHIN: right shin

RANK: right ankle

6 Feet

LHEE: left heel

LTOE: left foot just before big toe starts

LMT5: outside of left foot where toes start

RHEE: right heel

RTOE: right foot just before big toe starts

RMT5: outside of right foot where toes start


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Suit Front


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Suit Back

Suit Arm Suit Leg

4. Preparing Subject & Capturing


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a. Setting up the Database

Press the Data Management button. You will need to create a Database folder to put your capture sessions in. Use the green

button to create a top level, the yellow button to create a subject, and the grey button to create a session.

Setting Up Database

b. Calibration Capture Trial

Now we need to calibrate the motion capture subject. To do this we need to capture a session where the subject moves each joint

in their body so that vicon can predict the subject's range of motion and calculate the length of the subject's bones.

You should start with the motion capture subject in the middle of the room with their back straight, arms straight out with palms

facing down, and feet forwards. This is called a T-pose. You should begin and end every capture session in a T-Pose.

Now press the Capture button at the top, choose capture from the right sidebar, and when you are ready, press the start button.

When you are done, press stop.


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Capturing

c. Subject Calibration

In order to do the subject calibration, we need to load the data. Load the data by double clicking the blue X next to the capture

trial you just created.

Loading Data

IQ should automatically go to Post Processing. From the right Sidebar, Choose pipeline and select Subject Calibration from the


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drop down menu. Right-click on CircleFit, Reconstruct, Trajectory and choose run selected Op. You should now see points in

3D Workspace.

Reconstructing Points

Open the Subjects panel from the right sidebar. Press the Create Vicon Skeleton Template (VST) button. A box will come up

that asks which template you are using and what to name the subject. Find the place on the timeline where the subject is in the

T-Pose and press the G button (outlined in blue) followed by the T button.


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Adding Subject

Next you need to label the markers. Open labeling from the right sidebar. Select Sequence Mode, click on a marker, then click

on a marker in 3D Workspace to label it. You can disable the skeleton using the View Options pane on the left if it is in the way.


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Labeling

Now go back to the Pipeline pane on the right sidebar and run the rest of the pipeline. Now the skeleton's' motion should match

up with the markers. This even works in real time!


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Subject Calibration Complete

Before you go on to capture data, be sure to go back to the subjects pane and save the subject calibration by pressing the Export

Vicon Skeleton (VSK) button.

d. Capturing

You can capture using the same techniques you learned in the Calibration Capture Trial. Most notably, always begin and end in a

T-Pose. The post processing however will be different. All you need to do for post processing is choose the GeneralReconstructpipeline (instead of subject calibration) and run all operations.


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Post Processing with an Already Calibrated Subject

5. Exporting the Data

You will need two types of files to load the motion-capture data into MotionBuilder. You need a VSK for each subject

calibration and V file for each capture session.

To export your VSK, choose Subjects from the main menu and select "Export Vicon Skeleton Options..."

To export the V file, choose file from the main menu and select export. Choose *.v from the drop down menu of file types.

When the options panel comes up, be sure Include Markers is set to No, Local Bodies is set to Yes, and Global Bodies is set toNo.


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V-file Export Options

5. Getting Data Into Lightwave

a. Lightwave Export

The first step in exporting your data is to create and save a scene file that contains the character you want animated. Be sure to

have your skelegons converted to bones.

With your scene file loaded in layout, open the utilities tab, and under plugins, open the "Additional" menu and choose "Export

to FBX". From the menu that appears check only Models and Materials. This file can be loaded directly into MotionBuilder.

To get the menus you need,

Lightwave Export to FBX

b. MotionBuilder

First load the FBX export of your lws into MotionBuilder. This can be done simply by double clicking the file or opening

MotionBuilder and selecting Open from the File menu. Your model should appear, but the textures may not so don't worry.

To get all the windows you need, from the Layout menu (at the top) choose editing. You should have 4 windows, Viewer,

Character Controls, Transport Controls, Navigatior, and Asset Browser.


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MotionBuilder

The next step is to Characterize the model. You will have to do this for both the character model and mo-cap skeleton.

First you need your character model facing down the positive Z-Axis. You can rotate your model by clicking on it, or it's node in

the Navigator, then clicking the rotate button on the right and using the manipulator that appears to rotate the model.

You will also need to rotate the character's joints into the T-pose. You can do so by selecting and rotating the joints similarly to

how you rotated the character. Selecting the joints is easier if you enable X-Ray mode from the Display menu in the Viewer.

Ready to Start Characterization


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From the asset browser, in the directory tree click on Characters Then click and drag the character icon onto your character in

the viewer. You may need to drag the icon into your character's node in the scene if your skeleton is seperate from its model.

Character in the Asset Browser

A button labelled Characterize should pop up. Press it. If an error occured you may need to tell MotionBuilder what parts of

your model's skeleton are. If your skeleton has bone names that MotionBuilder recognizes, you should not get any errors and

can skip this next step.

In the navigator, double click the character you just created and open the Character Definition tab. Expand the section call "Base

(required)". You will need assign bones to each of these entries that are unassigned. To do this you need to switch to schematic

view.

Character Definition

From the View menu in the Viewer, click Schematic. This allows you to see all the bones in a graph structure. For each

unassigned model in the character, click that model in the schematic view, then hold Alt and click and drag to the empty box in

the navigator. If your have problems finding the bones you need, right-click the Viewer and choose Arrange All.


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Schematic View

Now you can check the characterize checkbox, and hopefully the characterization is accepted.

Characterize Complete

As an additional step you can enable floor contacts. You can enable it in the character settings tab in the Navigator. Simply

check the Feet Floor Contact checkbox to enable it, but you will need to adjust the position of the floor contacts in the Viewer


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Enabling Floor Contacts

Next, you should switch to an orthographic left or right view from the View menu in the Viewer to adjust the green dots that

represent the floor contacts.

Adjusting Floor Contact Positions

Now you will need to import the motion capture data and characterize it. You can get to the importer by opening Open Reality

-> Tools -> ViconGP Importer from the top menu.

To import the skeleton (vsk), check only "Always create models" and Import Skeleton(s) The skeleton should show up in the

viewer.


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Importing VSK

To import the motion (v), uncheck all options. This may take some time for longer animations. MotionBuilder may appear to

freeze.

Importing V

Now you should characterize your mo-cap skeleton in the same way you did your model. Face the character down the positive

Z-axis. The character should already be in the T-pose, otherwise use the trasport controls to find the T-pose. Then be sure to

characterize and reassign bones if needed. Name your characters if you did not already.

Now you can set your model to use the animation from the mo-cap skeleton. From the Navigator, double-click your character

and open the Character Settings. For Input Type, choose Character Input. Check the active checkbox, and set the Input Source to

the the name of your mocap character. Now your mo-cap skeleton and character should match up perfectly.

Assigning Motion Capture Animation

You should, at this point, adjust the height of the mo-cap skeleton to plant the model's feet on the ground.


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Motion Capture on a Character

When you are satisfied with your animation, from the Character Settings tab of your character model in the Navigator, press the

"Plot Character..." button and save the animation to the character's skeleton. You will get a dialog containing various options.

This is the point at which you may downsample your animation from 120fps to a more reasonable rate such as 30fps.

Plotting Options

The final step is to select your character, choose Export from the file menu, from the Save as type drop down, select "Kaydara

(animation only) (.fbx)" and save. Be sure to save only the takes that have animation.


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Export Options

c. The Maya Hack

As of this writing, Lightwave does not have a plugin that can load files from the latest version of MotionBuilder, so we have to

use Maya to load the FBX file and resave it as an earlier version to get it to load into Lightwave. To import, simply use Importfrom the File menu. Most of the options you are presented with here won't matter.

Maya Import

To export, use Export from the file menu. The most important dialog choice is to set the Export version to "FBX53_MB55".


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Maya Export

d. Lightwave Import

To get the animation back into Lightwave, first load up the lws you exported your model from in the Lightwave Export step. If

you don't have it, it should still work if you make a new scene and load the same character you had. Also make sure your

skelegons are converted to bones. Then from Utilities tab choose open the Additional menu under Plugins and choose "Mergewith FBX". Select your file, choose your take, and it should all be loaded in.

6. Clean up after yourself

Put back lenscaps if needed

Replace all markers and suit

7. System Operator's Section

The most important step that has not been covered in this tutorial, but may need to be performed is backfocusing the lenses. If

the camera's focal distance changes significantly, you will need to do this. Simply place markers around the perimeter of theviewing volume open the camera view split the view and pan so that you can see both the closest and farthest marker from the


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