When I create a new plane tangent to my sphere (revolutionized semicircle), I can't move it on the surface of the sphere. I would like the plane to always be normal at the center of the sphere, but in principle this is the purpose of the tangency.
I'm not sure I saw the problem well... The sphere alone is not enough, a second entity is needed to completely define the plan. Either a point in a 3D sketch that belongs to the plane, or a segment that defines the direction of the normal to the plane, or... By placing this second entity in a 3D sketch, the plane can be dynamically evolved by dragging it with the mouse.