Material Properties Explained

Assigning the correct material properties is essential for generating accurate lighting and daylighting simulations. LightStanza provides five distinct material types to help you precisely model how light interacts with the surfaces in your design.

Depending on your project's needs, you can toggle between Simple inputs for quick setups or Advanced inputs for high-fidelity simulations. This article discusses how each input parameter will affect calculation and rendering results in LightStanza.

1. Opaque

Use this material type for solid, non-transparent surfaces such as walls, ceilings, floors, and furniture.

Simple Parameters

Ref (Reflectance): The overall percentage of light that strikes the surface and bounces back into the space.

Advanced Parameters

Advanced settings allow you to break down reflectance by color channels and surface texture:

R, G, B (Red, Green, Blue): Individual color channel reflectance values. The photopic average (weighted average of these channels) represents the total reflectance.
S (Reflected Specularity): Determines the shininess of the surface, or the fraction of light that is reflected as a perfect mirror-like beam.
RA (Roughness Average): Dictates how blurry the reflections are. Higher values will create a textured appearance, while lower values will render as smoother surfaces.

2. Glass

This type is designed for standard, clear architectural glazing systems like windows, curtain walls, and skylights.

Simple Parameters

VT (Visible Transmittance): The percentage of the visible light spectrum that passes through the glass.

Advanced Parameters

Tr, Tg, Tb (Transmissivity Channels): The specific internal transmissivity values for the Red, Green, and Blue light spectrums.

Note: Just like with Opaque materials, the photopic average of these three channels establishes the total Visible Transmittance (VT) of the glazing.

3. Translucent

Perfect for materials that scatter light as it passes through, such as frosted glass, shades, or diffuse plastic panels.

Simple Parameters

SR (Specular Reflectance): Light reflected off the front surface like a mirror.
ST (Specular Transmittance): Light that passes directly through the material without being scattered (like a clear view window).
DR (Diffuse Reflectance): Light scattered uniformly back from the surface.
DT (Diffuse Transmittance): Light scattered in a Lambertian pattern as it passes through the material.
A (Absorption): The fraction of light absorbed by the material and converted to heat.

Advanced Parameters

R, G, B (Red, Green, Blue): Individual color channel reflectance values. The photopic average (weighted average of these channels) represents the total reflectance.
S (Reflected Specularity): The fraction of reflected light that behaves like a mirror.
RA (Roughness Average): The micro-texture of the surface, controlling the blurriness of surface reflections.
T (Diffuse Transmissivity): The fraction of light that successfully passes all the way through the surface and is scattered diffusely.
TS (Transmitted Specularity): The fraction of light transmitted cleanly as a direct beam (the light that does not get diffusely scattered).

4. Complex Glazing

For specialty or patterned glass types that cannot be easily defined by a single transparency value.

This option allows you to select from pre-configured manufacturer datasets for specialized glass types, such as fritted glass, micro-louvers, or patterned ceramic documentation.

5. Roadway

Specifically tailored for outdoor infrastructure and civil lighting design.

This material type utilizes standard roadway surface classifications defined by the Illuminating Engineering Society (IES). It accounts for the unique, highly directional reflectance characteristics (such as asphalt or concrete textures) required for precise roadway uniformity and glare calculations.