IfcSpecularRoughness

BACnet MVD

#### IfcSpecularRoughness

Natural language names

| Specular Roughness
| Rugosité pour le spéculaire

##### Semantic definitions at the type

Type definition

The IfcSpecularRoughness defines the datatype for the reflection resulting from the roughness of a surface through the height of surface impurities where the specular highlight is made sharper with small values for the roughness, such as 0.1. Applies to "glass", "metal", "mirror" and "plastic" reflection models. Larger values, close to 1.0 decrease the specular fall-off.

IfcSpecularRoughness is of type REAL. It is constraint to values between (and including) 0 and 1.

> NOTE The datatype relates to the definition of "shiness" in ISO/IEC 14772-1, which is the reciprocate value to the specular roughness.

> HISTORY New type in IFC2x2.

Formal Propositions

Rule | Description
--- | ---
WR1 | Specular roughness shall be given as a non-negative value less than or equal to 1.0

##### Formal representations

XML Specification
`<xs:simpleType name="IfcSpecularRoughness">
<xs:restriction base="xs:double"/>
</xs:simpleType>
`
EXPRESS Specification
`TYPE IfcSpecularRoughness = REAL;
WHERE
WR1 : {0.0 <= SELF <= 1.0}
END_TYPE;

EXPRESS-G diagram

`

References: IfcSpecularHighlightSelect

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