Irradiance

I know that a simple equation which allows to calculate "output power of a PV panel" from Solar Irradiance is:

P = eta x A x S

where:

• eta: PV panel efficiency;
• A: PV panel area;
• S: Solar Irradiance

I'm interested in calculating the output power of a fixed solar panel mounted (in the North Emisphere, if it's important) with an inclination (tilt angle) of 30° and South-oriented, for example.

I just downloaded hourly solar data from NSRDB dataset.

The downloaded "csv" file contains values of:

• DHI (Direct Horizontal Irradiance);
• DNI (Direct Normal Irradiance);
• GHI (Global Horizontal Irradiance)

How could I use these values to obtain the Solar Irradiance value (S) to use in the equation written in "bold" at the beginning of this post?

I guess that "S" is a GTI (Global Tilted Irradiance) and, anyway, I hope it could be simply derived from DHI/DNI/GHI values (data contained in the "csv" file I downloaded).

I need to calculate the irradiance emited by a blackbody between two given wavelenghts. If I understand correctly I should integrate Planck's wavelength distribution function between said wavelenghts. The problem is that I'm not sure how to integrate it, and, according to various integral calculators I've found, the resulting function is extremely complicated for my math level.

Any idea of how should I apporoach the problem?

I'm sorry if I'm not clear enough, english is not my first language and I'm not sure if I expressed myself correctly. Please ask if you need any clarification.

Thanks in advance.

EDIT: Solved! Forgot that f(mean x)*delta x was a thing.

EDIT2: man it would be so cool if reddit had LaTex support

Under Project->Settings:

So...
Irradiance Max Size is like the reflection probe's captured resolution right ?
The higher the resolution the better.

So what is Atlast Size ? Why is bigger better ? Isn't that the resolution size which is also the Irradiance Max Size ?

What even is this Atlas Subdiv thing ?

Wenqi Xian, Jia-Bin Huang, Johannes Kopf, Changil Kim

Project: https://video-nerf.github.io/Abstract: We present a method that learns a spatiotemporal neural irradiance field for dynamic scenes from a single video. Our learned representation enables free-viewpoint rendering of the input video. Our method builds upon recent advances in implicit representations. Learning a spatiotemporal irradiance field from a single video poses significant challenges because the video contains only one observation of the scene at any point in time. The 3D geometry of a scene can be legitimately represented in numerous ways since varying geometry (motion) can be explained with varying appearance and vice versa. We address this ambiguity by constraining the time-varying geometry of our dynamic scene representation using the scene depth estimated from video depth estimation methods, aggregating contents from individual frames into a single global representation. We provide an extensive quantitative evaluation and demonstrate compelling free-viewpoint rendering results.

https://reddit.com/link/k180xh/video/blkf26fwei161/player

Hello everyone. I am in the learning process of Blender, currently working on my own interior environment and I would like to use eevee for rendering. I have a problem with indirect light baking and irradiance volume (IV) in particular. Problem is that whatever I do, I am not able to get a satisfying result without shading issues or artifacts.

I watched numerous tutorials, problem is that all of them consider simple scenes such as plane, sphere and sunlight, or simple rectangular room with window and basic furniture, nothing really advanced. My interior is quite complex and it´s not shaped regularly, it includes some curved walls and numerous props. You can see part of the environment in attached pictures. Picture shows the best baking result so far but not good enough because it still has some artifacts and irregular light on the ground, particularly along the wall with light strip.

I spent 3 days and endless hours trying, doing bakes, different settings, different resolutions of IV, I tried one IV, more IVs for different parts of environment etc, unsuccessfully. I tried even some insane resolutions (50 by 50) but the result was shit, it was better with lower number of probes. With model like this, it is almost, if not completely impossible to place the volume without some probes being inside of geometry and causing problems. How would you solve this? Is it even possible? If I use more probes (higher resolution), I can´t avoid bugs, if I use less probes, diffuse light on the ground (mainly) looks bad. Sorry for long text but after so many unsuccessful attempts, I feel really desperate and I have no idea what to do. I also attached solid shading picture so you have idea about what my model looks like.

Best result but with few artifacts and diffuse light on the ground doesn´t look good.

Solid view of the environment

Some more shading issues

[SOLVED!!!!!!]

So I've followed the learnopengl.com tutorial for PBR. And everything was going smooth, I could create the cube map texture, the prefilter texture, and they all looked correct just as in the tutorial, however, when creating the irradiance map, it all fell apart, and resulted in this image, when rendered directly using the skybox shader:

https://preview.redd.it/4dbj0sqgk9c61.png?width=1920&format=png&auto=webp&s=c5427c9491c16ffb8acaea6d3948807ea834e5fb

https://preview.redd.it/2o4f6zehk9c61.png?width=1920&format=png&auto=webp&s=8383b84605f9c686b2eb2a95f8631ae932b21e58

An important piece of information is that the tutorial suggested we use 16-bit precision floating point texture, but that wasn't enough for me, so I used the RGBA32F format (the alpha channels is needed because I'm using compute shaders instead of invoking the fragment shader 6x with the overhead of changing the framebuffer context and I couldn't get it to work as an RGB32F texture) instead of the RGBA16F. This also means that the sun pixels are very bright, so this might be the cause of the problem, but a lot of these environmental maps contain very bright suns, so there must be a standard solution.

I tried filtering using more samples: the tutorial uses a sampleDelta of 0.025. The image above is using that value, but I tested 0.025 / 4, which is still not enough, and 0.025 / 8 just causes a driver timeout and a crash, on my RTX 2070 Super, while rendering a 32x32 texture, which lead me to think that there must be a problem with my texture creation, or something like that, because rendering that single 32x32 texture with around 250k samples total takes 5x more time then rendering the 1024x1024 prefilter map with it's 5 LOD levels, and using 1024x1024 samples per level. So, wtf?

I guess you'll want this information:

My texture creation process it this:

Equirectangular map: Bilinear filtering, clamp to edge

Environmental map: Trilinear filtering, and I had to create the mips before rendering, because apparently, the compute shader requires me to have an immutable texture, I use clamp to edge here as well, but I have to call glGenerateMipMaps to have all the mips available, not just 1 and all the others blank. (So this happens: I create the texture, call glTexImage2D 6x, set the filtering to trilinear, generate the mips, render to it, generate the mips again.)

Irradiance map: Bilinear filtering, clamp to edge.

So I've been following the series learnopengl.com, especially the PBR shaders. I've got a lot of OpenGL experience, but I've never worked with float textures.

So I'm creating every texture as in the tutorial, and the enviroment map is nicely created from the equirectangular map. However, when not directly sampling the enviroment map, but using the convulotion shader in the irradiance shader, I've got a very weird pattern, the pixels that reached the sun on the image were all white, except for some spheres at certain distances from the sun, which were a shade of yellow, and the sun was all black and blue. So I jumped into renderdoc, and all the white and other weird pixels were infinities, and the black and blue ones were caused by nans and infinities.

So I went back to the code, and it turns out that the sampled colour sometimes returns infinity, but only in certain cases (the spheres from the previous description). So when I made all infinities 1.0, the problem disappeared, no more nans and inifities, but the convulotion map was still very weird.

Before

After

Any help is appreciated! I have never dealt with nans and infinities, and I only have some experience with C/C++ floating points and their properties. How can the shader sample infinities? I checked in renderdoc, and the equirectangular map and the environment map are all correct with their original intensities. I can link the renderdoc results (the prefilter map in it is an older version with just directly sampling the environment map, but I suppose the problem is the same so it shouldn't make a difference.

The renderdoc file is uploading, once it's done, I'm gonna link it here: https://drive.google.com/file/d/1kToEjjKcZHMGbDV2tSbBE8dAGVgKTpUU/view?usp=sharing

Is there any way to get solar irradiance (W/m2) forecast data/previsions for tomorrow? Websites like weather underground have information about today's and past solar irradiance, but I would like to get the forecast (from weather services) for tomorrow. I've searched everywhere and can't find this information.

Hey guys! Check out my new video on Effect of Variable Irradiance on a MPPT System on MATLAB/Simulink,I'm sure it would be of some use to you now or in future🙂

Video link

I am testing the power density of grow lamps that claim to have specific power at a square centimeter at some distance from the lamp

For example, a light will output 635 nm and 850 nm wavelengths. At 6 inches from the lamp I should measure 25 milliwatts per wavelength.

Formula is

635 nm 25 mW/cm2 at 6 inches

850 nm 25 mW/cm2 at 6 inches

What is the name of the device that measures this way?

Using 5mW laser diodes (linked example), how do I calculate the irradiance? I am trying to get an irradiance of 3.5mW/cm^2 from a distance of ~1-2 cm.

Hey guys! Check out our new video on Effect of Variable Irradiance on a MPPT System on MATLAB/Simulink,I'm sure it would be of some use to you now or in future🙂

Video link

Hey guys! Check out our new video on Effect of Variable Irradiance on a MPPT System on MATLAB/Simulink,I'm sure it would be of some use to you now or in future🙂

Video link