Gets or sets the X value of this Size3D structure.
member X : float with get, set
The X value of this Size3D structure. The default value is 0.
The X, Y, and Z values must be non-negative.
Size3D and Rect3D are not typically used in XAML, because no settable properties exist in the WPF 3D object model that use those types.
The following example shows how to check if two Size3D structures are equal. It also shows how to assign values to a Size3D structure when the structure is being declared and after the structure has been declared.
Size3D StructureSystem.Windows.Media.Media3D Namespace