FME supports translation of 3D geometry from one format to another, provided that each format itself supports 3D. The extent of 3D support is limited by the level of each format’s own 3D support. If one format supports solids and another supports only faces, the solids may be converted to faces during the translation. Because of this, each combination of reader and writer will have its own unique characteristics and should be tested. It is also important not to assume a particular transformer will support 3D until you have verified it first.
As with other enhancements to FME, the first step is the extension of core infrastructure and new geometry model, in this case to handle 3D constructs. Over time, this enhanced 3D support will be implemented throughout FME transformers and formats where this provides the most value.
A face is a planar area in 3D space. The planar structure can be a polygon, an ellipse, or a donut (IFMEArea).
The planar area has a concept of a surface normal, a vector that points outwards perpendicular from the area. The direction of the surface normal in an IFMEFace is determined by using the right-hand rule - if the fingers of your right hand curl along the order of the vertices, the direction that the thumb points to is the direction of the surface normal.
Contains: IFMEArea (1)
Contained by: IFMECompositeSurface, IFMEMultiSurface
A solid is a solid volume in 3D space, defined by a collection of connected surfaces. The exterior surface is represented by an IFMECompositeSurface, with the additional requirement that this composite surface must be closed, in order to form a volume.
An IFMEBRepSolid can contain spatial voids. Each spatial void is represented by an IFMECompositeSurface, representing an interior surface. This definition is analogous to the inner boundaries that define donut holes.
In general, an IFMEBRepSolid must contain one exterior surface and zero or more interior surfaces.
Contains: IFMECompositeSurface (0..n)
Contained by: IFMECompositeSolid, IFMEMultiSolid, IFMECSGSolid