Honeybee Intermezzo 5: Assign material optical properties to the HB model
For a more accurate Daylight simulation, you should assign the values of the optical properties for each material in the corresponding surfaces. Specifically, you should specify the:
- Reflectance (for opaque materials), which is a percentage indicating the amount of light that is reflected by the surface when the light falls into it (the higher the reflectance, the more light is reflected).
- Transmittance (for transparent materials), which is a percentage indicating the amount of light that is transmitted through the window (the higher transmittance, the more light passes through the window.)
Important to note: HB gives the option to specify also other optical parameters, such as roughness and specularity, but since these are mostly useful for visual purposes (renderings) or very specific types of analyses (solar convergence), they will not be used in this phase.
Step 1: Create the Radiance modifiers per material
For each material of your project, you should create a different Radiance modifier, gathering its optical properties in it.
In the HB-Radiance » Modifiers you can find the different material categories that you may use. For this tutorial example:
1. Create a HB-Radiance » Modifiers » HB Glass modifier and use a Params » Input » Number Slider to define the transmittance of the window.
Give a value of 0.87, which corresponds to clear transparent glass, and assign it to the '_trans' input.
Create a Params » Input » Panel component and write "Glass_Window" in order to give a characteristic name for the material. Connect it to the '_name_' input.
2. For all the materials, except glass and metal surfaces, an opaque modifier should be used as a starting base.
Thus, create 4 HB-Radiance » Modifiers » HB Opaque modifier to define the reflectance of the rest of the materials. For this tutorial, create Params » Input » Number Slider and Params » Input » Panel components and assign:
-For the floor: Reflectance: 0.2 / Name: Dark timber/carpet
-For the walls: Reflectance: 0.5 / Name: Light Grey concrete
-For the shades & doors: Reflectance: 0.35 / Name: Light timber
-For the interior walls & ceiling: Reflectance: 0.7 / Name: White paint
Step 2: Create the Modifier Subsets per face type
1. To assign the material properties to the corresponding HB faces, create:
a. An HB-Radiance » Modifiers » HB Exterior modifier subset
b. An HB-Radiance » Modifiers » HB Subface modifier subset
c. An HB-Radiance » Modifiers » HB Interior modifier subset
d. An HB-Radiance » Modifiers » HB Shade modifier subset
2. Connect the ‘modifier’ result of each Radiance material modifier to the corresponding face input. For this tutorial:
- Connect the ‘Dark timber/carpet’ modifier to ‘_exposed_floor_’ (HB Exterior Modifier Subset) and ‘_interior_floor_’ (HB Interior Modifier Subset).
- Connect the ‘Light Grey concrete’ modifier to ‘_exterior_wall_’ (HB Exterior Modifier Subset) and ‘_interior_shade_’ (HB Shade Modifier Subset).
Important to note: The interior shades in our example refer to the extruded borders of the aperture and, therefore, to the wall thickness.
- Connect the ‘Glass_Window’ modifier to ‘_window_’ and ‘_operable_’ (HB Subface Modifier Subset), so as to apply to both operable and non-operable windows.
- Connect the ‘Light timber’ modifier to ‘_exterior_door_’ (HB Subface Modifier Subset) and ‘_exterior_shade_’ (HB Shade Modifier Subset).
- Connect the ‘White paint’ modifier to ‘_interior_wall_’, ‘_ceiling_’ (HB Interior Modifier Subset) and ‘_exterior_roof_’ (HB Exterior Modifier Subset).
Step 3: Assign the Modifier Subsets to the HB Room
1. Create a HB-Radiance » Modifiers » HB ModifierSet.
2. Connect the result of each Modifier Subset created in Step 2 to the respective input.
3. Create a Params » Input » Panel component in order to give a characteristic name for the Modifier Set you are creating. In our example, you can write "Room1_Materials".
4. Connect the ‘mod_set’ result of the HB ModifierSet component to the ‘_mod_set_’ input of the HB Room component.
Step 4: Visualize & Check
In order to quickly check the attributes that are assigned to each face:
1. Create a Honeybee » Visualize » HB Label faces component.
2. Connect the ‘model’ result from HB Model to the ‘_hb_objs’ input.
3. Create a Honeybee » Visualize » HB Face Attributes or a HB-Radiance » Basic Properties » HB Face Radiance Attributes component. Select the attribute which you want to be demonstrated.
For this tutorial we are going to select the Modifier attribute from the HB Face Radiance Attributes component.