In FME what is the diffrence between composite-surface and multi-surface? As far as I can tell when reading the description they do pretty much the same thing. How do they diffrientiate and why would I use one rather then another?
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Hi @hadhafang, in my understanding, those two geometry types are different in not only internal data structure (IFMECompositeSurface and IFMEMultiSurface) also the object to represent conceptually. That is, a composite surface is a geometry that represents a continuous surface of a single object, a multi-surface is an aggregate that represents surfaces (regardless of whether those are continuous or not) of one or more objects.
For example, the surface for each individual box can be represented by either a composite surface or a multi-surface (both consisting of six Faces), but an aggregate of the surfaces of the two boxes should be represented by a multi-surface (or an aggregate), conceptually.
However, in fact, IFMECompositeSurface geometry can represent non-continuous surface too, such as the two boxes. FME internal geometry data structures are lenient to unexpected or invalid geometry data.
Hi @hadhafang,
Adding onto takashi's wonderful answer, composite surfaces also have consistent front / back directions on faces ('continuous surfaces'), which could be important for adding on textures.
Check out this webinar at about 4:00 mins to hear Dave explain the differences. Here are some more quick links to read a bit more on the topics: IFMECompositeSurface, and IFMEMultiSurface.
Hi @hadhafang, in my understanding, those two geometry types are different in not only internal data structure (IFMECompositeSurface and IFMEMultiSurface) also the object to represent conceptually. That is, a composite surface is a geometry that represents a continuous surface of a single object, a multi-surface is an aggregate that represents surfaces (regardless of whether those are continuous or not) of one or more objects.
For example, the surface for each individual box can be represented by either a composite surface or a multi-surface (both consisting of six Faces), but an aggregate of the surfaces of the two boxes should be represented by a multi-surface (or an aggregate), conceptually.
However, in fact, IFMECompositeSurface geometry can represent non-continuous surface too, such as the two boxes. FME internal geometry data structures are lenient to unexpected or invalid geometry data.
Hi @hadhafang,
Adding onto takashi's wonderful answer, composite surfaces also have consistent front / back directions on faces ('continuous surfaces'), which could be important for adding on textures.
Check out this webinar at about 4:00 mins to hear Dave explain the differences. Here are some more quick links to read a bit more on the topics: IFMECompositeSurface, and IFMEMultiSurface.