body tracking based interaction
In the OP's context, if the expression has been referred to throughout as body-tracking, that is, with a hyphen, then it would be body-tracking based interaction.
On the other hand, if the document consistently refers to the concept as body tracking without a hyphen, then it would naturally be body tracking based interaction.
In no case can it be body tracking-based interaction, which can imply aNan entirely different idea.
It is not always necessary, especially now and in future, to hyphenate -based.
