Lux measurement using Irradiance feature

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Dade
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Re: Lux measurement using Irradiance feature

Post by Dade » Wed Feb 06, 2019 10:57 am

It is a lot easier to start from the C++ code and leave the OpenCL code as next step. The CPU code is here: https://github.com/LuxCoreRender/LuxCor ... tracer.cpp

Just looks for "irradiance" and you will find the 2 places (direct light + indirect light) where it is compute.
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pro
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Re: Lux measurement using Irradiance feature

Post by pro » Thu Feb 07, 2019 12:36 pm

Dade wrote:
Wed Feb 06, 2019 10:57 am
It is a lot easier to start from the C++ code and leave the OpenCL code as next step. The CPU code is here: https://github.com/LuxCoreRender/LuxCor ... tracer.cpp

Just looks for "irradiance" and you will find the 2 places (direct light + indirect light) where it is compute.
Do you think it´s theoretically possible to readapt those pieces of code to output lux (somehow reusing directLight/indirectLight variables and than devide by m²) or did I totally misinterpreted this (my physics knowledge is not that strong in this topic)?

pro
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Joined: Wed Dec 12, 2018 7:48 am

Re: Lux measurement using Irradiance feature

Post by pro » Tue Feb 19, 2019 10:27 am

Dade wrote:
Wed Feb 06, 2019 10:57 am
It is a lot easier to start from the C++ code and leave the OpenCL code as next step. The CPU code is here: https://github.com/LuxCoreRender/LuxCor ... tracer.cpp

Just looks for "irradiance" and you will find the 2 places (direct light + indirect light) where it is compute.
.IES files carry only information about visible light, so if there is no radiation in other non-visible spectrum, illuminance should be equal to irradiance in that case. I hope that's the case in LuxCore and that heuristics in irradiance feature doesn't include radiation in other specturms? If that's right, obtained "irradiance feature" output should be just multiplied by a precalculated scalar to get illuminance.

Another question that I have related to optimization - is it possible to render only irradiance pass without rendering default passes i.e. Combined aka RGB_IMAGEPIPELINE (by commenting out lines in C++ code and recompiling)? Or Irradiance feature somehow depends on calculation of those passes?

Thank you very much for your time and help!

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Dade
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Re: Lux measurement using Irradiance feature

Post by Dade » Tue Feb 19, 2019 11:58 am

pro wrote:
Tue Feb 19, 2019 10:27 am
Another question that I have related to optimization - is it possible to render only irradiance pass without rendering default passes i.e. Combined aka RGB_IMAGEPIPELINE (by commenting out lines in C++ code and recompiling)? Or Irradiance feature somehow depends on calculation of those passes?
Both irradiance AOV and RGB_IMAGEPIPELINE are the product of the same process so disabling the second AOV will have no tangible benefits.
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