Creating a 3D Irradiance Sensor

The 3D Irradiance Sensor allows you to analyze the light contributions for each face of a geometry. Each selected face becomes a sensor and computes irradiance (in Watt/m2) or illuminance (in Lux).

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

To create a 3D Irradiance Sensor:

  1. From the Light Simulation tab, click 3D Sensors > 3D Irradiance .
  2. In the 3D view, click and select one or more faces or bodies to include to the sensor.
    Important: Make sure to select geometry (face or body) that is not tangent to another geometry (face or body) on which a 3D Irradiance sensor is already applied. Two tangent faces, each one having a 3D Irradiance sensor applied, are not supported in simulation.
  3. If you want to use a XM3 template to define the sensor, in XM3 template, click Browse and load a *.xml file.

    A XM3 template allows you to apply a *.xml file containing measure data exported from an existing *.xm3 file. Measures are automatically created in the new *.xm3 file generated during the simulation based on the data contained in the template file.

    Note: The *.xm3 file generated is not related to the measure template file. If you modify the template file, the *.xm3 file generated remains the same.
  4. In the General section, select the Type of the sensor:

    • Photometric to compute the luminous intensity (in cd) and generate an extended map for Virtual Photometric Lab.

      The illuminance levels are displayed with a false color and you cannot make a spectral or a colorimetric analysis with an extended map.

      Note: In case of a photometric result generation, the International Commission on Illumination (CIE) defines the visible spectrum as follows: "There are no precise limits for the spectral range of visible radiation since they depend upon the amount of radiant flux reaching the retina and the responsivity of the observer. The lower limit is generally taken between 360 nm and 400 nm and the upper limit between 760 nm and 830 nm".

    • Radiometric to compute the radiant intensity (in W.sr-1) and generate an extended map for Virtual Photometric Lab.

      The illuminance levels are displayed with a false color and you cannot make a spectral or a colorimetric analysis with an extended map.

    • Colorimetric to compute the color results without any spectral layer separation (in cd or W.sr-1)
  5. From the Integration type drop-down list, define how the illuminance is integrated in the sensor:
    • Select Planar for an integration that is made orthogonally with the sensor plan.

    • Select Radial if you need to follow specific street lighting illumination regulations.

      With the Radial type, the calculation is based on the standard EN-13201 which gives mathematical formulas equivalent to different types of illuminance.

      The integration direction must be orthogonal to avoid wrong flux computation.

  6. If you want to generate a ray file containing the rays that will be integrated to the sensor, select the Ray file type:
    • SPEOS without polarization generates a ray file without polarization data.
    • SPEOS with polarization generates a ray file with the polarization data for each ray.
    • IES TM-25 with polarization generates a *.tm25ray file with polarization data for each ray.
    • IES TM-25 without polarization generates a *.tm25ray file without polarization data.

    The ray file is only generated at the end of the simulation.

    Note: According to the geometry on which you use the 3D Irradiance Sensor, a same ray can be stored several times at different locations leading to an over-estimation of the flux.
    Note: The size of a ray file is roughly 30 MB per Mray. Check the free space on the hard drive before generating a ray file.
    CAUTION: If the surface that will be used for the creation of the ray file is fully absorbent (SOP set to Mirror 0%), all rays are absorbed and no ray will be integrated in the ray file. This ray file will be empty.
  7. From the Layer drop-down list, select:
    • None to get the results of the simulation in one layer.
    • Source if you have created more than one source and want to create one layer per active source in the result.
  8. If you selected Photometric or Radiometric, in the Additional measures section, define which type of contributions (transmission, absorption, reflection) need to be taken into account for the integrating faces of the sensor.
  9. If you selected Colorimetric, in the Wavelength section, define the wavelength characteristics:
    1. With Start and End, define the wavelength interval of the spectral data.
    2. With Sampling or Resolution, define the number of wavelengths or the step between each wavelength to take into account in the wavelength interval.
The 3D Irradiance Sensor is created in the 3D view and the Speos tree.