IElement required extension methods

The following points outlines the use of the dimensional interfaces as well as extension methods required to be implemented by them for them to function correctly in the Spatial_Engine methods.

Please note that for classes that implement any of the following analytical interfaces, an default implementation already exists in the Analytical_Engine and for those classes an implementation is only needed if any extra action needs to be taken for that particular case. The analytical interfaces with default support are:

Analytical Interface	Dimensional interface implemented
INode	IElement0D
ILink<TNode>	IElement1D
IEdge	IElement1D
IOpening<TEdge>	IElement2D
IPanel<TEdge, TOpening>	IElement2D

Please note that the default implementations do not cover the mass interface IElementM.

1. If the BHoM class implements an IElement interface corresponding with its geometrical representation:

   Interface	Implementing classes
   IElement0D	Classes which can be represented by Point (e.g. nodes)
   IElement1D	Classes which can be represented by ICurve (e.g. bars)
   IElement2D	Classes which can be represented by a planar set of closed ICurves (e.g. planar building panels)
   IElementM	Classes which is containing matter in the form of a material and a volume

2. It needs to have the following methods implemented in it's oM-specific Engine:

   Interface	Required methods	Optional methods	When
   IElement0D	Geometry() SetGeometry(Point point) HasMergeablePropertiesWith(IElement0D)
   IElement1D	Geometry() SetGeometry(ICurve curve) HasMergeablePropertiesWith(IElement1D)	Elements0D() SetElements0D( List<IElement0D> newElements0D) NewElement0D(Point point)	IElement1D which endpoints are defined by IElement0D
   IElement2D	OutlineElements1D() SetOutlineElements1D( List<IElement1D> outlineElements1D) NewElement1D(ICurve curve) HasMergeablePropertiesWith(IElement2D)	InternalElements2D() NewInternalElement2D() SetInternalElements2D( List<IElement2D> internalElements2D)	If the IElement2D has internal elements
   IElementM	MaterialComposition() SolidVolume() or VolumetricMaterialTakeoff()

3. Spatial_Engine contains a default Transform method for all IElementXDs. This implementation only covers the transformation of the base geometry, and does not handle any additional parameters, such as local orientations of the element. For an object that contains this additional layer of information, a object specific Transform method must be implemented.