There isn’t a way to automatically apply these to your polyline via the Entity API, but you can use those algorithms to pre-compute your positions array. The Entity API does however have built-in support interpolation for position property used to draw a path. See Cesium Sandcastle
Hey Hannah !
Thank You for Your reply.
Well… I just have a polylines which is updated each couple of seconds, and I would like to have interpolation on them. to be more… smooth in some way.