The second tab in the settings are shown if the license for dynamic daylight, for calculating daylight factor is enabled. By default, this settings tab is hidden.
Calculate Daylight Factor
By checking this box, the Radiance/Accelerad calculation will be run. The daylight factor calculation will be skipped if you uncheck this box. This is handy when you only want to get Daylight Area Ratio calculation results, and have quicker results. Calculating daylight factor might take 0:20 - 2:00 (m:ss) per room.
Calculation Engine
You can select two engines to calculate daylight factor. Dependent on the chosen engine the daylight factor results might vary.
- Radiance
This is the industry standard daylight factor calculation. This engine is CPU based, and should always work on your PC. Naviate Daylight installs radiance automatically, so no third party software is required. - Accellerad
Accelerad has the same workflow as radiance, while key ray trace calculations are done over the GPU instead of over the CPU. This improves performance massively, depending on your card's CUDA compute capabilities.
This engine only works with Nividia Graphic Cards, as it uses Nvidia Optix. So this option will not work on computers with Intel or AMD graphic drivers.
You must update your Nividia driver enabling the Optix ray tracing engine enable in order to be able to run Accelerad. If not installed, or if no compatible graphics card found, this selected engine results in an error message.
Custom Rendering Options
Default Naviate Daylight Radiance Rendering Options are set to:
-aa 0.15 -ab 4 -ad 256 -ar 32 -as 20 -st 1 -lw 0.05 -dc 0 -dj 0.7 -dp 32 -dr 0 -ds 0 -u-
Xinaps and Symetri found out this rendering settings to be the best balance between calculation time and the quality of results. These settings have the quickest calculation time, whilst generating mediocre daylight factor, lux and uniformity ratio results.
We recommend to apply our default settings, so that all projects and rooms are calculated equally, and results can be better compared with eachother. It is not advisable to manually change these settings unless you have first understood the various Radiance commands and their respective values.
You can set your own rendering options by checking the box "Custom Rendering Options".
More information about these radiance settings can be found in the Radiance Documentation:
- Setting Rendering Options
- RTRACE Documentation
- Default Radiance Parameters for Sefaira Daylighting Visualization from Sefaira Documentation
Make sure that you follow the conventions for specifying variables (e.g. "-ab", not "ab").
Apply the option "-u-" to make sure result values for Daylight Factor, Lux and Uniformity Ratios remain equal every time you recalculate. If this option is not set, result values differ every time you recalculate.
Here's a list of rendering options commonly applied by other Radiance users:
| Application Type | Radiance Parameters | Calculation Time for one simple room. | Results DF / Uniformity |
| Sefaira (gives you the freedom to play with -ab, which you can set to 2, 3, or 4. We recommend to use -ab 4) | -aa 0.15 -ab 4 -ad 256 -ar 32 -as 20 -st 1 -lw 0.05 -dc 0 -dj 0.7 -dp 32 -dr 0 -ds 0 -u- | 0:04 | 3.03% / 25.58% |
| Radiance Medium Quality | -aa 0.15 -ab 4 -ad 800 -ar 1904 -as 128 -st 0.1 -lw 0.001 -dc 0.5 -lr 8 -dj 0 -dp 4096 -dr 1 -ds 0.3 -ms 0.01 -ss 1 -av 0.01 0.01 0.01 -dt 0.1 -u- | 5:58 | 30.5% / 27.52% |
| Daysim 3.0 | -aa 0.1 -ab 5 -ad 1000 -ar 300 -as 20 -st 0.15 -lw 0.004 -lr 6 -dj 0 -dp 512 -dr 2 -ds 0.2 -u- | 0:48 | 3.13% / 12.73% |
| DIVA | -aa .25 -ab 2 -ad 1024 -ar 128 -as 1024 -st .85 -lw .05 -lr 4 -dc .25 -dj 0 -dp 128 -dr 0 -ds .5 -dt .5 -u- | 0.04 | 2.67% / 19.04% |
| IDA ICE EQUA, low precision | -aa 0.25 -ab 3 -ad 1024 -ar 0 -as 512 -st 0.85 -lr -4 -lw 1.0E-6 -dj 0.1 -ds 0.5 -dr 0 -dp 125 -dc 0.25 -dt 0.5 -u- | 0:07 | 2.92% / 26.32% |
| IDA ICE EQUA, medium precision | -aa 0.2 -ab 5 -ad 2048 -ar 0 -as 1024 -st 0.5 -lr -6 -lw 1.0E-6 -dj 0.5 -ds 0.25 -dr 1 -dp 256 -dc 0.5 -dt 0.25 -u- | 0:30 | 3.16% / 30.57% |
| IDA ICE EQUA, high precision | -aa 0.10 -ab 7 -ad 2048 -ar 0 -as 1024 -st 0.15 -lr -8 -lw 1.0e-6 -dj 0.7 -ds 0.15 -dr 3 -dp 512 -dc 0.75 -dt 0.05 -u- | 2:28 | 3.19% / 31.35% |
| IDA ICE EQUA, super precision | -aa 0.05 -ab 10 -ad 2048 -ar 0 -as 1024 -st 0.15 -lr -11 -lw 1.0e-6 -dj 0.7 -ds 0.15 -dr 3 -dp 512 -dc 0.75 -dt 0.05 -u- | 13:10 | 3.18% / 31.51% |
| DesignBuilder, Fast | -aa 0.3 -ab 1 -ad 256 -ar 128 -as 128 -u- | 0:01 | 2.40% / 7.36% |
| DesignBuilder, Standard | -aa 0.25 -ab 2 -ad 512 -ar 256 -as 256 -u- | 0:01 | 2.68% / 16.90% |
| DesignBuilder, Good no interpolation | -aa 0.00 -ab 4 -ad 1024 -ar 512 -as 512 -u- | 0:01 | 3.04% / 23.15% |
| DesignBuilder, Good | -aa 0.22 -ab 4 -ad 1024 -ar 512 -as 512 -u- | 0:20 | 3.09% / 28.73% |
| DesignBuilder, Accurate | -aa 0.20 -ab 5 -ad 2048 -ar 512 -as 1024 -u- | 1:07 | 3.16% / 30.54% |
| DesignBuilder, High Quality | -aa 0.18 -ab 7 -ad 4096 -ar 1024 -as 2048 -u- | 12:00 | 3.19% / 31.43% |
Wall Offset of the calculation points
You can include an offset distance value to remove daylight factor calculation points close to the walls of the room. This will remove the dark spots in the corners from the equation. This area can be excluded, as this area is not count as usable area of the room.
Distance between the calculation points
This distance value defines the grid density of the daylight factor points for calculating the daylight factor of each room. The higher this value the faster the calculation, the less daylight factor points will be generated in a room to take the average daylight factor from. Would you like to have a more detailed color visualization? Then make this value smaller.
Room specific values
Below a list of daylight values, varying per room.
Calculation Height
The Calculation Height is the height of the measurement pane where the luminance is measured. For corridors and other circulation rooms, the luminance should be measured at floor height whereas the walkable area . For office rooms and other occupiable rooms, the luminance should be measured at table height.
This value can be set in the room parameter by the user.
Luminance
Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through, is emitted from, or is reflected from a particular area, and falls within a given solid angle.
For each daylight point on a grid, with an offset to the room bounding walls, the luminance will be calculated. This results in a list of values, whereas the minimum is the lowest calculated value, the maximum luminance is the highest calculated value, and the average luminance is the average of all luminance values.
Daylight Factor
The Dalight Factor is the ratio of the light level inside a structure to the light level outside the structure. It is defined as DF = (Ei / Eo) x 100%
where, Ei = illuminance due to daylight at a point on the indoors working plane, Eo = simultaneous outdoor illuminance on a horizontal plane from an unobstructed hemisphere of overcast sky.
For each daylight point on a grid, with an offset to the room bounding walls, the daylight factor will be calculated. This results in a list of values, whereas the minimum daylight factor is the lowest calculated value, the maximum daylight factor is the highest calculated value, and the average daylight factor is the average of all daylight factor values.
Required Daylight Factor
The required daylight factor is the minimum daylight factor value for each given room. This value can be set in the room parameter by the user.
Uniformity Ratio
The Uniformity Ratio is the ratio between the minimum luminance and the average luminance in the room. The lower this ratio, the darker spots the room has in relation to the average luminance.
3D Visualization
After the calculation is finished, you can click the 3D visualization. The result will look something like this:
Word Report Template
The following table can be added to the Word Template. Read more on how to edit Word Templates>>
#X_WTF_MEETSDAYLIGHTRATIO | #X_WTF_NUMBER | #X_WTF_NAME | #X_WTF_LEVEL | #X_WTF_MIN_LUM | #X_WTF_AVG_LUM | #X_WTF_MAX_LUM | #X_WTF_MIN_DF | #X_WTF_AVG_DF | #X_WTF_MAX_DF | #X_WTF_REQDF | #X_WTF_UNRAT | #X_WTF_CALCHGT |
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All these hashtags starting with #X_WTF... will be replaced by the column results per room, and localized header name when generating the Word Report from the Naviate Daylight Application.
Also, the following variables can be added:
- #X_COG_OFFSET ; Calculation pane offset from the walls
- #X_COG_DENSITY ; Calculation pane measurement points grid density
- #x_images ; will be replaced by heatmap images automatically generated from the app's 3D visualization.