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A calibration file (often referred to as a Standing Trial or a Static Trial) is a short motion capture of the subject in a stationary pose. Marker positions are averaged automatically over all frames to compensate for noise in the data. NOTE: If the subject moved during the standing trial, you can specify a subset of frames using the [Modify Frame Range For Static Calibration] command from the Model Menu items. Anatomical markers or Calibration markers are placed at anatomically relevant locations (e.g. palpable bony landmarks near segment endpoints). Tracking markers are placed at convenient locations for tracking the segments. Suggested rules for marker placement on rigid clusters is described in the following article: Cappozzo A, Cappello A, Della Croce U, Pensalfini (1997) Surface-Marker Cluster Design Criteria for 3-D Bone Movement Reconstruction. IEEE Transactions on Biomedical Engineering, 44 (12), p 1165-1174.

1. Ensure that version 3.0 or later of Visual3D has been downloaded and installed.

2. Download the [sample data].

3. Save this file in the folder where you plan to save your motion capture files.

NOTE: The download contains the end result of this tutorial. It may be useful as a secondary resource for verifying your progress.

4. Launch the Visual3D program from the Start menu. The program will open to the main workspace.

Before completing this tutorial please review the [3D Viewer Animation Controls].

1. From the Model menu, select Create → Hybrid Model from C3D file.

2. A dialog titled Select the calibration file for the new model will appear; Select Sub01_StandingStaticCal01.c3d Click Open.

3. Visual3D will switch to Model Building mode automatically. The 3D viewer will display the average value of the marker locations from the standing file. The dialog bar to the left of the screen will contain a list of segments, which by default will contain only a segment representing the Laboratory (e.g. Motion Capture Volume).

Note: You may need to modify the lab coordinate system in Visual3D to properly view the subject. Under Settings select Modify Lab Coordinate System, change the A/P axis to -X and Axial to +Z.

Note: Your screen may look slightly different.

Throughout this tutorial, play with some of the 3D view options to familiarize yourself with these options:

With your mouse, use the 3D Viewer Animation Controls to rotate/pan your view of the model.

1. Click the View Target ID toggle button on the toolbar until the target names appear.

2. Click the View Segment toggle button on the toolbar until the pelvis bone disappears (the same effect can be achieved by pressing F5 on your keyboard).

3. Click the View Segment Geometry toggle button on the toolbar until you toggle off geometric view the pelvis (the same effect can be achieved by pressing F7 on your keyboard).

4. Click the View Segment Lines toggle button on the toolbar until you toggle off the yellow lines which connect the segment end points.

There are many possible markers for a pelvis segment that make sense anatomically, and have a history in the biomechanics community. Visual3D offers 3 default pelvis segments:

1) Visual3D Pelvis - The default pelvis segment in Visual3D is labeled a Visual3D Pelvis since the pelvis can be constructed as any other segment. Visual3D inherited this definition from MOVE3D (the precursor software to Visual3D) and has been used by the staff in the Physical Disabilities Branch at the NIH for more than 20 years.

2) Coda Pelvis - The CODA pelvis defines the location of the Hip Joint Centers using regression equations from the Bell and Brand articles.

3) Helen Hayes (Davis) Pelvis - The Helen Hayes (Davis) pelvis defines the location of the Hip Joint Centers using regression equations from the Davis article.

In this tutorial we are presenting the CODA pelvis: 1. On the segments tab:

1. From the Segment Name box, select Pelvis.

2. From the Segment Type box, select Coda.

3. Click Create.

4. Click Build Model to build the segment. You should now see a pelvis segment on your standing model. If you do not see the pelvis segment after clicking Build Model, double check the values you entered in the last step.

It is often helpful to isolate the segment's coordinate system in order to validate that it is setup correctly. This view can also help you visualize where the center of gravity for a segment is located. Follow the procedure below to isolate the segment's coordinate system by toggling off the other views. When you are done you will be left with the Coordinate System of the Pelvis as represented by a Red Line (x-axis), Green Line (y-axis) and a Blue Line (z-axis).

Note: Each of the view buttons is a toggle button and will either toggle on or off a particular view.

Click the Views Segment toggle button caption on the toolbar until the pelvis bone disappears (the same effect can be achieved by pressing F5 on your keyboard).

Click the Views Segment Geometry toggle button caption on the toolbar until you toggle off geometric view the pelvis (the same effect can be achieved by pressing F7 on your keyboard).

Click the Views Segment Lines toggle button caption on the toolbar until you toggle off the yellow lines which connect the segment end points.

Double-click on the Pelvis segment and select . Select , and select the A/P axis to be +Y, and axial axis as +Z.

You may skip to this section if you wish. It is possible to replace the ”bones” with another bone or object file. As a ridiculous example, you can change the pelvis model to display a skull rather than the pelvis bones. This example can be found here.

Save often to prevent loss of files due to power outages or Windows errors.

Save the Workspace to a .cmz file

Maintain a series of .cmz files as you work so that you can revert to a previous step.

From the File menu, click on Save As.

In the Save As dialog box label your file MyTutorial1.cmz, navigate to the location of your choice and click Save.

Save the Model Template

Save the segment definitions as a model template (mdh) file to allow you to re-create models using the same marker set. From the Model menu select Save Model Template.

In the Save As dialog box label your file Tutorial_ModelTemplate.mdh, navigate to the location of your choice and click Save.

Apply the Model Template

Now that the model template exists, you can use this template on other data sets.

From the Model menu select Apply Model Template.

In the dialog box select the appropriate .mdh file.

Create Thigh Segment:

1. From the Segments tab, select Right Thigh in the Segment Name drop down list box

2. Click Create. A new tab labeled Right Thigh will open.

3. In the Right Thigh tab, enter these values:

4. Click Build Model. A 3D image of a thigh will appear.

Note: If you receive an error message about inertial properties and custom segments, you may have entered an incorrect number for the proximal radius.

5. Modify the Right Thigh coordinate system by clicking Segment Properties and Modify Segment Coordinate System. Change the A/P axis to +Y and the Axial Axis to +Z.

6. Click Close Tab before proceeding.

Note: Closing the tab will not affect the model in any way.

Create Virtual Knee Joint Center:

1. Click Landmarks button

2. Click Add New Landmark button

3. Create Landmark: RIGHT_KNEE

4. Offset Using the Following AXIAL Offset: 0.5

5. Check: Offset by Percent (1.0 = 100%)

6. Check: Calibration Only Landmark

Create Right Shank Segment:

1. In the Segments tab, select Right Shank in the Segment Name box.

2. Click on the Create Segment button.

3. In the Right Shank tab, enter these values:

4. Click Apply and Build Model

5. Go to Segment Properties and Modify Segment Coordinate System. Change the A/P axis to +Y and the Axial Axis to +Z.

Create Virtual Ankle Center

1. Click Landmarks button

2. Click Add New Landmark button

3. Create Landmark:// RIGHT_ANKLE//

4. Offset Using the Following AXIAL Offset: 0.5

5.** Check:** Offset by Percent (1.0 = 100%)

6. Check: Calibration Only Landmark

Create Virtual Toe Center

1. Click Landmarks button

2. Click Add New Landmark button

3. Create Landmark:// RTOE_FT//

4. DO NOT Check: Offset by Percent (1.0 = 100%)

6. Check: Calibration Only Landmark

Create Right Foot Segment:

1. In the Segments tab, select Right Foot in the Segment Name box.

2. Click on the Create Segment button.

3. In the Right Shank tab, enter these values:

4. Click Apply and Build Model

5. Go to Segment Properties and Modify Segment Coordinate System. Change the A/P axis to +Y and the Axial Axis to +Z.

Create Thigh Segment:

1. In the Segments tab, select Left Thigh in the Segment Name box.

2. Click on the Create Segment button.

3. To Automatically Populate Left Thigh Information:

4. OR Manually enter the values for the left thigh:

5. Click on Build Model. A 3D image of a thigh will appear. 6. Click on Close Tab before proceeding.

Create the Left Knee:

1. Click Landmarks button

2. Click Add New Landmark button

3. Create Landmark: LEFT_KNEE

4. Offset Using the Following AXIAL Offset: 0.5

5. Check: Offset by Percent (1.0 = 100%)

6. Check: Calibration Only Landmark

Create Left Ankle Center

1. Click Landmarks button

2. Click Add New Landmark button

3. Create Landmark:// LEFT_ANKLE//

4. Offset Using the Following AXIAL Offset: 0.5

5.** Check:** Offset by Percent (1.0 = 100%)

6. Check: Calibration Only Landmark

Create Left Toe Center

1. Click Landmarks button

2. Click Add New Landmark button

3. Create Landmark:// LTOE_FT//

4. DO NOT Check: Offset by Percent (1.0 = 100%)

6. Check: Calibration Only Landmark

Create Shank Segment:

1. In the Segments tab, select Left Shank in the Segment Name box.

2. Click on the Create Segment button.

3. To Automatically Populate Left Shank Information:

4. OR Manually enter the values for the left shank:

5. Click on Build Model. A 3D image of a shank will appear. 6. Click on Close Tab before proceeding.

Create Foot Segment:

1. In the Segments tab, select Left Foot in the Segment Name box.

2. Click on the Create Segment button.

3. To Automatically Populate Left Foot Information:

4. OR Manually enter the values for the left foot:

5. Click on Build Model. A 3D image of a foot will appear. 6. Click on Close Tab before proceeding.