IFC 4.3.2.20240904 (IFC4X3_ADD2) under development

SurfaceGenusBeforeFeatures

Semantic definition

The Surface Genus of the evaluated representation items before applying product-level geometric features such as openings and projections.

Surface Genus is a topological measure that represents the number of "holes" or "handles" on a surface. For example, a sphere has genus 0, and a torus has genus 1.

Computed using the Euler characteristic:

$$\chi=V-E+F$$

With the numbers of vertices (V), edges (E) and faces (F)

$$\chi=2−2g−b$$

With surface genus (g) and the number of boundaries (b) the latter zero in case of an enclosed volume.

Referenced in
Qto_BodyGeometryValidation
Table A

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