I am a bit confused on how Cesium calculates geodetic and geocentric surface normal. Planes, generated from calculated normal do not actually tangent to ellipsoid surface in a given point, more then, the plane created from geodetic surface normal is just the same as one generated from geocentric surface normal.
Example & why do I need this
In this Sandcastle XYZ axis along with planes that should be tangent to ellipsoid are drawn when you click on the globe surface.
What I need is to get an XY plane tangent to Ellipsoid at given point and then project other points onto this plane. The problem is as I see the plane is not tangent to ellipsoid at all.
By the way - when I use built in method:
Cesium.EllipsoidTangentPlane(); I also get strange result - plane is still not tangent to ellipsoid and also floating somewhere in space. Here is sandcastle.
Appreciate any help because I do not understand what happens here.