when running C:\ProgramData\NVIDIA Corporation\OptiX SDK 5.0.0\SDK-precompiled-samples\optixMDLExpressions.exe
and pressing one time “e” which is the “perez_sun_and_sky” (“Perez all weather sun and sky model”) one,
a moving circular white pixel on the sphere is visible.
Is that desired?
Or is that caused by the exception program ?
That’s the reflection of the sun in that Perez sun and sky environment simulation.
Thank you for your answer and the clarification, Detlef.
So I set direct_normal_irradiance: 0.0 and now the sun is gone. Great!
But also the corona is gone. Is there a way to only use that corona without the sun itself?
That Perez sun and sky function is part of the built-in MDL base:: module contained inside the MDL SDK library shipping with the example. Other than changing its exported parameters, there is no way to change that specific implementation.
I don’t know how its arguments affect the visual results because I have never used that myself.
If the sun irradiance value controls both the sun disk and the sun’s corona, then I wouldn’t know how to change that. It’s meant to produce the correct results and that includes the sun disk.
You could try to use a small non-physically correct low-dynamic range value for the irradiance or experiment with the other parameters and see if that is able to control the effect you desire.
Other than that, there was a Preetham sun and sky environment implementation inside the older OptiX 3.9.1 SDK examples where you can choose to render the sun disk manually.