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Contacts Points in MVN

Since the release of MVN 2019.0, we offer the possibility to analyze contact points in MVN. This allows the detection of the interaction of the avatar with the environment. Such as foot contacts when walking, pelvis contacts when sitting or even both hands and foot contacts when climbing. 

Contact Points in MVN

In MVN, the contact points are defined for each point defined for a certain segment. In the Navigator window of the MVN, in the Segments tree structure, the points defined for each segment can be found there. 

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It is important to notice that before reprocessing the data, multiple contact points are allowed for one segment. But after HD reprocess, this data is cleaned and a single point of a certain segment is chosen for each frame to have a predominant foot contact and all the other are ignored. 

Additionally, you can edit the contact points by selecting a certain region with the mouse or right click in the selected contact point.

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Contact Points in MVNX

When a mvn file is exported in mvnx format, a different computation of the contact points is made. The main reason is to provide a more clear and usable data to the user. In MVNX format, only 4 foot contacts are defined:

  • LeftFoot_Heel
  • LeftFoot_Toe
  • RightFoot_Heel
  • RightFoot_Toe

Each of this contacts is described as a boolean in the mvnx file. This means that "1" there is contact and "0" there no contact. When opening a MVNX file, for each frame there is information about <footContact>. This is an array of 4 boolean values, which the first value corresponds with the left heel, the second one with the left toe, the third value with the right heel and the fourth value with the right toe. An example of a gait cycle is shown below: 

[1 1 0 0] - the left foot is on the ground and the right foot in the air

[0 1 0 0] - the left toe is on the ground, but the left heel is lifted

[0 1 1 0] - the left toe is on the ground and the right heel has landed

[0 1 1 1] - the left toe is on the ground as well as the right foot

[0 0 1 1] - the left foot is in the air and the right foot on the ground

[0 0 0 1] - the right toe is on the ground, but the right heel is lifted

[1 0 0 1] - the right toe is on the ground and the left heel has landed

[1 0 0 0] - the left heel is on the ground, but the left toe is lifted

[1 1 0 0] -  the left foot is on the ground and the right foot in the air

 

 

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