This information is for Vicon ProCalc 1.5. For up-to-date help, see the latest ProCalc documentation.

Vicon ProCalc banner

About this tutorial

ProCalc 1.3 and later enables you to generate VSK files based on calculations specified in a ProCalc variables scheme. This tutorial explains how to do this and the benefits of this approach. 

This tutorial uses as an example a VST created with Nexus and CGM2.3. If you want to use a different VST, make sure you replace any 1-degree-of-freedom (hinge) joints with 3-degree-of-freedom (ball) joints (see Updating the joints in the VST).

About VSK/VST files

The Vicon VSK/VST file format is primarily used in the Vicon Nexus software to specify labeling skeleton templates. The labeling skeleton contains a set of relationships between motion-captured markers and an underlying skeletal structure, which Vicon Nexus uses to automatically label (auto-label) markers. Users of Vicon Nexus select a template (VST), and then scale/calibrate the template to the current subject that is being captured (which generates a corresponding VSK file), so that the auto-labeler can do its job.

The VST/VSK file format is a generic format that can be used to specify any relationship between markers and segments, including those that define biomechanical models – in other words, where the segments’ positions estimate anatomical segments. ProCalc enables you to specify the marker-segment relationships that are normally used in a biomechanical model in the VST/VSK file format without having to manually edit a text file. Instead, you generate a VSK from a model that is defined in ProCalc.

Generating a VSK from ProCalc has two major benefits:

  • When you set up a customized biomechanical model in ProCalc, you can use the same model for labeling.
  • You can improve the labeling for CGM, or generate real-time kinematics.

Some of the default VST files that are supplied with Nexus use a 1?degree-of-freedom (hinge) joint at the knee. Before using the VSK with ProCalc as described in this tutorial, replace the 1-degree-of-freedom joint with a 3-degree-of-freedom (ball) joint. For more information, see Updating the joints in the VST.

About the files for this tutorial

To follow this tutorial, download and unzip this file:

Copy the files to these locations:

File nameDescriptionLocation
CGM23.vstLabeling skeleton templateC:\Users\Public\Documents\Vicon\Nexus2.x\ModelTemplates
CGM2.3.InputParamSchemeInput parameters schemeC:\Users\Public\Documents\Vicon\Eclipse\InputParamSchemes
CGM2.3.VarSchemeVariables schemeC:\Users\Public\Documents\Vicon\Eclipse\VariableSchemes

These files contain complete information for this tutorial, so you can follow the instructions without having to enter additional data.