Should we deal with it in a smart enough navigation or just navigate to the surface?
Xiaocong: Depends on how larg the stereo angle is.
If it is large enough we should put it into ACTS.
The description of the surface can be created easily, but the intersection is more problematic.
But when we can intersect efficiently, it is not a problem.
So for Runge-Cutta we need to add the straiht line intersect.
Xiaocong: That is the really long term approach.
It is nice that we have a source like this around.
Could be useful to have it very clear, even with unit tests.