White pixel in MDL Expressions Sample (in OptiX 5.0.0 SDK)
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 ?
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 ?

Disclaimer: No warranty. No legal advice.

#1
Posted 01/08/2018 11:31 PM   
That's the reflection of the sun in that Perez sun and sky environment simulation.
That's the reflection of the sun in that Perez sun and sky environment simulation.

#2
Posted 01/09/2018 02:26 PM   
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?
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?

Disclaimer: No warranty. No legal advice.

#3
Posted 01/09/2018 08:41 PM   
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.
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.

#4
Posted 01/10/2018 04:41 PM   
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