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 # SourceAmbientCIEOvercast – Creating an ambient source CIE standard overcast sky

 Last update: 22.04.2026 

The following script sample shows you an example on how to create an Ambient Source CIE Standard Overcast Sky.

```ironpython
overcastSource = SpeosSim.SourceAmbientCIEOvercast.Create()
overcastSource.ZenithDirection.Set(GetRootPart().CoordinateSystems[0].Axes[1])
overcastSource.SpectrumType = SpeosSim.SourceAmbientCIEOvercast.EnumSpectrumType.LibrarySpectrum
overcastSource.SpectrumValueLibrary = ".\\SPEOS input files\\Sky.spectrum"

```