IfcSurfaceSide是一个表面的负、正或两面都被引用的表示。
注释类型根据ISO10303-46中定义的表面_侧改编。
IFC2.0中的新枚举类型
Enumeration definition
| Constant | Description |
|---|---|
| POSITIVE | The side of a surface which is in the same direction as the surface normal derived from the mathematical definition. |
| NEGATIVE | The side of a surface which is in the opposite direction than the surface normal derived from the mathematical definition. |
| BOTH | Both, positive and negative side. |
EXPRESS Specification
TYPE IfcSurfaceSide = ENUMERATION OF (
POSITIVE,
NEGATIVE,
BOTH);
END_TYPE;
原文：https://www.cnblogs.com/herd/p/14181066.html