LuxCoreRenderer for light measurement

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msi
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Joined: Fri Jun 22, 2018 8:49 am

LuxCoreRenderer for light measurement

Post by msi » Fri Jun 22, 2018 9:05 am

Hello,

I wanted to ask if (and how) it is possible to use LuxCoreRenderer to get information about the Light (quantity and color) that arrives in a specified point somehwere in a scene using the global illumination algorithms implemented in the renderer. The points of measurement I want to use are not bound to a surface, usually they are in the air somehwere in a scene. My first approach would be to render a qube map with a low resolution from that point in the scene and then accumulate the resulting color values but maybe there is a better / faster way to achieve that goal?.
thx.

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Dade
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Re: LuxCoreRenderer for light measurement

Post by Dade » Fri Jun 22, 2018 9:16 am

msi wrote:
Fri Jun 22, 2018 9:05 am
I wanted to ask if (and how) it is possible to use LuxCoreRenderer to get information about the Light (quantity and color) that arrives in a specified point somehwere in a scene using the global illumination algorithms implemented in the renderer. The points of measurement I want to use are not bound to a surface, usually they are in the air somehwere in a scene. My first approach would be to render a qube map with a low resolution from that point in the scene and then accumulate the resulting color values but maybe there is a better / faster way to achieve that goal?.
You could use a panoramic camera to collect the radiance arriving in a 3D point. You will obtain an image like:

Image

The other option is to implement a special type of camera, it could takes a list of points to evaluate and it would produce just a text file with numerical values. This would be far better if you have to measure several 3D points in the same scene.
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msi
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Re: LuxCoreRenderer for light measurement

Post by msi » Mon Jun 25, 2018 5:53 am

Hallo, thanks for the answer. I thought about that durign the weekend. Even if this would be already great, i think it does not coved the direct light influence from a light source since the light source is usually not visible in a rendered picture. Is there a posibilit to do the same caclulation that ar usually done on a surface that is hit by a ray just somewhere in the space of a scene? Or is there a better way to take the direct illumination into account?

Thx

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Dade
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Re: LuxCoreRenderer for light measurement

Post by Dade » Mon Jun 25, 2018 8:13 am

msi wrote:
Mon Jun 25, 2018 5:53 am
Hallo, thanks for the answer. I thought about that durign the weekend. Even if this would be already great, i think it does not coved the direct light influence from a light source since the light source is usually not visible in a rendered picture. Is there a posibilit to do the same caclulation that ar usually done on a surface that is hit by a ray just somewhere in the space of a scene? Or is there a better way to take the direct illumination into account?
You could use the DEPTH AOV and camera position to rebuild the position of the small area patch seen by a pixel and use the Irradiance AOV to obtain the irradiance received by the patch. But it is very stretched and works only for surfaces, not arbitrary points in space.

It looks more and more like you need to modify the code to obtain what you need.
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msi
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Re: LuxCoreRenderer for light measurement

Post by msi » Mon Jun 25, 2018 9:19 am

ok, i was already aware of that, but sometimes it is just worth to ask before. Thank you anyway

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