Compare and contrast use of extrusion node, ElevationGrid node and ...

Compare and contrast use of extrusion node, ElevationGrid node and IndexedDace set in x3d. This is a review question, thus anything can be used directly (no references) from the documentation.

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ElevationGrid node represents a rectangular grid with variable height in the plane of the local coordinate system with y coordinate equal to zero. Its geometric model can best be described by a scalar array of those height values that specify the height of a surface above each point of the corresponding grid.
By comparison, IndexedFaceSet node represents a 3D shape formed by building faces from polygons using the vertices which are listed in the coord field. This consists of a coordinate node that describes the 3D vertices referenced by the coordIndex field. IndexedFaceSet uses the The indices from coordIndex field specify the polygonal faces using indexing method to the coordinates from Coordinate node. All faces from the IndexedFaceSet must contain at least three non-coincident vertices, vertices that define a planar polygon and the vertices that describe a non-self-intersecting polygon....