IfcSurfaceStyleRendering
Definition from IAI: IfcSurfaceStyleRendering holds the
properties for visualization related to a particular surface side style. It allows rendering properties to be defined by: NOTE: If the reflectance method, as given by the
IfcReflectanceMethodEnum is "GLASS", the transmission factor controls
the level of transparency in the glass, In this case the transparency factor is
interpreted as transmission factor.
NOTE: The inherited attribute
SurfaceColour is treated as the ambient colour and specifies how much
ambient light from light sources this surface shall reflect. Ambient light is
omnidirectional and depends only on the number of light sources, not their
positions with respect to the surface.
NOTE: Both Transparancy and
TransmissionColour (or factor) are included, the following definitions
apply
NOTE: IFC 2x Edition 2
adds additional capability for presentation of physically accurate illuminance
on surfaces. VRML type rendering and rendering based on ISO 10303-46 continues
to be supported by a subset of the information. For reflectance equations and
further information about the surface style properties and its processing, see:
NOTE: The definition of
IfcSurfaceStyleRenderingProperties includes the definitions as found in
ISO 10303-46:1994, in particular of:
In addition to the attributes
as defined in ISO 10303-46, i.e. ambient_reflectance, diffuse_reflectance,
specular_reflectance, specular_exponent, and specular_colour, the current IFC
definition adds other colours, reflectance factors and specular
roughness..
HISTORY: This is new Entity in
IFC 2x.
EXPRESS specification:
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| Transparancy | : | Definition from ISO/CD 10303-46: The degree of transparency is indicated by the percentage of light traversing
the surface. Definition from VRML97 - ISO/IEC 14772-1:1997: The transparency field specifies how "clear" an object is, with 1.0 being completely transparent, and 0.0 completely opaque. If not given, the value 0.0 (opaque) is assumed. |
| DiffuseColour | : | The diffuse part of the reflectance equation, can be given as either a colour or a scalar factor. The diffuse colour field reflects all light sources depending on the angle of the surface with respect to the light source. The more directly the surface faces the light, the more diffuse light reflects. The diffuse factor field specifies how much diffuse light from light sources this surface shall reflect. Diffuse light depends on the angle of the surface with respect to the light source. The more directly the surface faces the light, the more diffuse light reflects. The diffuse colour is then defined by surface colour * diffuse factor. |
| TransmissionColour | : | The transmissive part of the reflectance equation, can be given as either a colour or a scalar factor.
It only applies to materials which Transparancy field is greater then zero. The transmissive colour field specifies the colour that passes through a transparant material (like the colour that shines through a glass). The transmissive factor defines the transmissive part, the transmissive colour is then defined by surface colour * transmissive factor. |
| DiffuseTransmissionColour | : | The diffuse transmission part of the reflectance equation, can be given as either a colour or a scalar
factor. It only applies to materials which Transparancy field is greater then zero. The diffuse transmission colour specifies how much diffuse light is reflected at the opposite side of the material surface. The diffuse transmission factor field specifies how much diffuse light from light sources this surface shall reflect on the opposite side of the material surace. The diffuse transmissive colour is then defined by surface colour * diffuse transmissive factor. |
| ReflectionColour | : | The reflection (or mirror) part of the reflectance equation, can be given as either a colour or a scalar
factor. Applies to "glass" and "mirror" reflection models. The reflection colour specifies the contribution made by light from the mirror direction, i.e. light being reflected from the surface. The reflection factor specifies the amount of contribution made by light from the mirror direction. The reflection colour is then defined by surface colour * reflection factor. |
| SpecularColour | : | The specular part of the reflectance equation, can be given as either a colour or a scalar factor. The specular colour determine the specular highlights (e.g., the shiny spots on an apple). When the angle from the light to the surface is close to the angle from the surface to the viewer, the specular colour is added to the diffuse and ambient colour calculations. The specular factor defines the specular part, the specular colour is then defined by surface colour * specular factor. |
| SpecularHighlight | : | The exponent or roughness part of the specular reflectance. |
| ReflectanceMethod | : | Identifies the predefined types of reflectance method from which the method required may be set. |
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