The use automated centre of mass nodes for dynamic grounded and airborne key frame animation

  • Kenneth Pitts

Student thesis: Doctoral Thesis


All real objects move around their centre of mass, whereas 3D characters are generally animated from their pelvis. Dynamic character movements can be complex to animate realistically as the centre of mass changes position with pose. This leads to complex pelvis trajectories which are not easy to judge correctly. The instantaneous centre of mass has been used infrequently as a control node to allow the character to follow a simpler animation path that is divorced from the requirements of the pose. The relationship between the pose and the centre of mass node, or COM node, could be controlled automatically. This type of control, however, is not widely used.
In this research an automated COM node system is developed using a design science research methodology with the goal of establishing the benefits and shortcomings of such systems across a range of dynamic animation scenarios.
This research shows that use of an automated COM node showed the characteristics expected of a physically derived motion, assisted with balance and improved editability. Poses remained fully determinate and recallable whether grounded, airborne or switching between the two. It also highlighted potential nonlinearities in the relationship between the pose definition and COM node and the need for key frames for the COM node to be generated automatically for grounded movements
Date of AwardMar 2021
Original languageEnglish
Awarding Institution
  • University of Portsmouth
SupervisorBrett Stevens (Supervisor), Paul Charrise (Supervisor) & Hui Yu (Supervisor)

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