Creating a Natural Light Ambient Source

A Natural Light Ambient Source generates light from the sky according to the time, location and the turbidity. The luminance varies according to where you look.

Important: This feature is only available under Speos Premium or Enterprise license.

To create a Natural Light Ambient Source:

  1. From the Light Simulation tab, click Ambient and click Natural Light .
    A preview of the sun and the 4 cardinal points appear in the 3D view. The sun's position is computed according to the timezone and location set.

  2. In the 3D view:
    • If you want to modify the Zenith direction, click and select a line (normal to the ground).
    • If you want to modify the North direction, click and select a line corresponding to the Y axis.
    • or click and select a coordinate system to autofill the Axis System.
    Note: The North direction corresponds to the rotation axis of the earth projected on the ground.
    Note: If you define manually one axis only, the other axis is automatically (and randomly) calculated by Speos in the 3D view. However, the other axis in the Definition panel may not correspond to the axis in the 3D view. Please refer to the axis in the 3D view.
  3. From the Sun type drop-down list:
    • Select Automatic to automatically calculate the sun position according to the north direction and the selected Timezone and location.
    • Select Direction to manually set the Sun Direction by clicking a line in the 3D view.
  4. Set the Turbidity of the sky, that is the cloudiness of the environment. The lower the turbidity, the clearer the environment.

    The luminance is automatically calculated according to the level of turbidity of the sky.

    Tip: The turbidity usually varies between 1.9 and 9.9.
    Note: When turbidity is higher than 6, a part of the luminance distribution of the sky is computed using the overcast sky luminance distribution formula. We recommend you not using a turbidity higher than 6 with natural light ambient source. Otherwise, limit the altitude of sun to reduce the error.
  5. If you want to use the sun only in simulations, uncheck With Sky.
  6. Set the Time zone and location:
    • If you want to set the coordinates manually (longitude and latitude), from the Location drop-down list, select User.
    • If you want to use the night sky model, adjust the Date and time.
  7. In Optional or advanced settings , adjust the size of the rays displayed in the 3D view.
The Ambient Source appears in the Simulation panel. In the 3D view, the four cardinal points and a representation of the sun are displayed.