---
title: "Defining the foot segments"
canonical: "https://help.vicon.com/space/ProCalc16/12649459/Defining%20the%20foot%20segments"
format: markdown
---
Define the foot segments using the anterior-posterior axis **LHEE/RHEE** to **LTOE/RTOE** as their major axes.

Note that the minor axis in CGM is not yet defined in CGM2.3: this is added in the next version (CGM2.4). (This can also be implemented in ProCalc, but is not part of this tutorial.)

**To define the feet:**

1. Create two vectors, **LFootAP** and **RFootAP**, from **LHEE/RHEE** to **LTOE/RTOE**.
2. Create two segments, **L_Foot** and **R_Foot**, using **Origin A, X-axis=B, Z-Axis=BxC**, specifying A=**LAJC/RAJC**, B=**LFootAP/RFootAP** and C=**LTibiaML/RTibiaML.**   
When defining the **L_Foot**, flip the **LTibiaML**.

> ✅ **Tip**   
> ✅ To define foot flat for the static trial, when defining the feet, change the **XYZ** drop-down for the **LFootAP/RFootAP** and **LTibiaML/RTibiaML** vectors to **XY** instead of **XYZ.**  
> ✅ The Z-coordinate of the vectors is ignored, and the foot is modeled as flat on the ground in the static trial.