How can I show the past orbital trajectory of two orbiting bodies?

I am currently modelling an ellipsoid and a sphere orbiting one another using vtkParametricEllipsoid and vtkSphereSource respectively. At each timestep, they read coordinates from a data file and update their positions using the vtkActor.SetPosition function. What I would like is to show the past trajectory of these bodies and preferably for them to slowly fade out over time so that newer points on the trajectory are more prominent. How can I achieve this? Are there any examples of this being done? I am using vtk in Python. By the way, this is my first time using VTK so don’t assume any knowledge.

Hi Leon,
I think vedo: vedo ( which is python and uses VTK may be doing more-or-less what you want.
Have a look at the “simulations” section and either the airplanes or double pendulum 3d demos.

Hi Ruben,

My group wants these animations to be written in pure VTK, and I have already written quite a bit of the code in VTK. I’ve found the vtkPolyLine class but am still figuring out how to update it for the purpose of animation.