Finally to get the number of interaction we can create a custom feature for the number of track children with the tag "Contact".

We Start by opening the Custom Features editor and adding a new Group Statistics feature.

This new custom feature has been configured as follows:

1. The name is set to reflect the data it represents. In this case, the number of children objects that make contact.
2. The Feature on which this custom is configured has been set to the number of children (# Children).
3. The Tag field has been set to only include objects with the tag "Contact".
4. The value that is added as a column in the table is the Count.

When finished the number of children that make contact will appear in the objects table as a feature of the tracks.

This feature can also be added as a feature filter for the tracks to quickly get a count of tracks that make contact.

Source: Image courtesy: Dr. B. Stolp, Heidelberg University, Center for Integrative Infectious Disease Research (CIID)