---
title: "Step 1 - Defining the static model"
canonical: "https://help.vicon.com/space/ProCalc16/12650643/Step%201%20-%20Defining%20the%20static%20model"
format: markdown
---
Before you begin, ensure you have <span style="color: #172b4d">unzipped</span> the ProCalc Tutorials data as described in [About the data for this tutorial](https://vicon-help.atlassian.net/wiki/spaces/ProCalc16/pages/12649924/Vicon+ProCalc+6DOF+Modeling+Tutorial#AboutModel).

Start ProCalc, and on the **Data Management** tab, navigate to the **6DOF Data** folder and double-click the trial called **Static** to load it.

The markers from the static trial are displayed in the 3D workspace:

![image](media://5b2ca75f-c667-4f1d-9a82-399c557160a5)

> ✅ **Tip**  
> ✅ To toggle the display of all the labels, select the option at the top right of the workspace, or press CTRL+SPACE.


**To define the static model:**


1. At the top of the **Variables** tab, click the Create button > Macro (inline-media-image)

, to create a new scheme. Name it appropriately, eg, **6DOF Shoe Model**, and press the Enter key to accept the choice.
2. At the bottom of the tab, click the Add button > Macro (inline-media-image)

 to add a new variable. To define the ankle joint center as the half-way point between the lateral and medial malleolae (LANK and LMMA), do the following:
  1. For the **Function** group, select **Point** and for the function **Halfway between A and B**.
    The A and B drop-downs activate, and the type for these defaults to **Point**.
  2. Click on the two malleolae markers in the 3D workspace.
    The left ankle joint center is defined.
  In the text box for the variable's name, type **LAJC**.
3. Click > Macro (inline-media-image)

 and > Macro (inline-media-image)

 to automatically define the right joint center based on what you chose for the left side. For the rest of this tutorial, you can use this trick to define all Right variables, based on already-defined Left ones – in the interests of readability it is not repeated every time.
4. Define the foot coordinate system as being aligned with the laboratory coordinate system for the static trial, with origin at the ankle joint center. To do this:
  1. Click the > Macro (inline-media-image)

 button again to add another variable.
  2. Name the variable **LeftFootAnatomical**.
  3. Select the **Segment** group and the function **Origin A, X-Axis=B, Z-Axis=B x C**.
  4. Select **A=LAJC**, **B=Lab X-Axis** and **C=Lab Y-Axis**.   
The coordinate system is displayed in the 3D workspace.
5. Define the foot's technical coordinate system, ie, the one based on the marker clusters only. To do this:
  1. Click > Macro (inline-media-image)

 again.
  2. Name the variable **LeftFootTechnical**.
  3. Select **Segment** and **From 3-marker cluster A, B, C**.
  4. Select the three heel cluster markers LHEE_Upper, LHEE_Lower and LHEE_Lateral.   
The technical coordinate system is displayed in the workspace – the orientation of this is not important.
6. To save the variable scheme, click the > Macro (inline-media-image)

 button at the top of the tab.
7. Click the **Parameters** tab. Click the Create button to create a new Parameter scheme, name it **6DOF Shoe Model**, and press Enter.  
Our aim is to calculate the transformation from the technical to the anatomical coordinate system and save this as a parameter, so that the same transformation can be used in the dynamic trial to get the anatomical coordinate system, even if the anatomical markers are no longer present. To do this:
  1. Create a parameter by clicking the Add button > Macro (inline-media-image)

 and entering **LeftFootAnatomicalToTechnical**.
  2. Select the **Average** function group and the function **Variable A's local coordinates in Variable B [Event A, Event B]**.
  3. For the **Type** select **Segment** and select **LeftFootAnatomical** for A, **LeftFootTechnical** for B, **First Valid Frame** for Event A and **Last Valid Frame** for Event B.  
I**mportant**: Ensure that the **Model Parameter** check box is selected.   
This saves the parameter's value to a file which is subsequently used for the dynamic processing.
8. After having defined this parameter for both the left and right sides, make sure that you click the > Macro (inline-media-image)

 button to save the parameter scheme.