vtkTubeFilter - representation and intersections

Dear VTK users/developers,

I have a number of vtkPolyData in 3D, each of those representing some sort of trajectory. Every point of each polydata is a result of real-life measurements, and in this specific case the measurements have an error (uncertainty) that increases the further we move away from the first point in the polydata.

I’d like to show this uncertainty - and I can do it by using a vtkTubeFilter with varying radius. The problem is, these uncertainties are not the same with respect to azimuth and inclination - i.e., the uncertainty in azimuth can be different from the one in inclination. So what I would need is some sort of vtkTubeFilter with an elliptic cross-section, with the axes of the ellipsis varying in length at each point. Does anyone know if it is possible to build something like that in VTK?

Furthermore, some of these polydata get “too close” to one another, and I’d like to show when this happens - which would require to find where two vtkTubeFilters intersect one another and then display the result as points, or a fatter tube, or something like this. Do you have a suggestion on how I could go to implement this?

Thank you in advance for your help.