Honeybee and climatestudio Daylight simulation vs. IESVE Daylight simulation

grasshopper honeybee[+]
,
1

Hi,
Dear Support Team,
I am currently conducting lighting simulations for a room with identical geometry and material properties across three software platforms: IESVE, ClimateStudio, and Honeybee, all utilizing the Radiance engine. However, I have observed discrepancies in the results and would appreciate your assistance in understanding the potential causes, particularly related to IESVE.

Here are the key details of my simulations:

  • Date and Time: December 21, 12:00 PM
  • Sky Model:
    • In IESVE: Intermediate Sky with Sun (as referenced in the sky file Dec21_1200_is.sky).
    • In Honeybee and ClimateStudio: CIE Intermediate Sky with Sun.

Given that ClimateStudio and Honeybee use the CIE Intermediate Sky with Sun, I suspect the discrepancies with IESVE may stem from differences in Radiance parameters, sky model implementation, or internal processing methods. Could you please clarify the following:

  1. How does IESVE’s Intermediate Sky with Sun differ from the CIE Intermediate Sky with Sun used in Honeybee and ClimateStudio? Are there specific assumptions or modifications in the IESVE sky model?
  2. Are there any known differences in how IESVE processes geometry, materials, or Radiance outputs compared to other Radiance-based tools like Honeybee and ClimateStudio?
  3. Could you suggest steps to align IESVE’s simulation results with those of Honeybee and ClimateStudio?
    climate studio - 21december -12pm.pdf (1.4 MB)
    IESVE_ 21 december_ 12pm.pdf (219.5 KB)
    Honeybee- 21december -12pm_compressed.pdf (220.9 KB)

Best regards,

2

For Cross-Software Comparison in Radiance-Based Daylighting Simulations

When comparing daylighting simulation results across different software platforms, it is essential to ensure that all relevant settings are consistent. Please follow the checklist below to validate and align the simulation parameters:

  1. Surface Material Properties
    Verify the default surface properties in all three software tools. Pay particular attention to parameters such as:
  • Reflectance
  • Transmittance
  1. Radiance Rendering Parameters
    Check the default Radiance settings used by each tool. Important parameters include:
  • Ambient bounces (-ab)
  • Ambient accuracy (-aa)
  • Other relevant Radiance rendering options
  1. Sky Model Configuration
    Examine the default sky definitions employed by the software. Ensure that the same Radiance sky model (e.g., Perez, CIE, or uniform) is used in all cases.

It is critical that all these settings are made identical across the tools in order to ensure a fair and meaningful comparison.

Please note: this validation and adjustment process can be time-consuming, often requiring several hours to complete.

Best of luck with your simulation analysis!

3 Likes