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Questions tagged [radiosity]

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15 votes
2 answers
697 views

Problem with definition of BSDF and radiance

When I was reading theory behind physical based rendering I noticed that definition of BSDF and radiance has some problems. For example BSDF of purely specular surfaces is zero almost everywhere and ...
2 votes
1 answer
188 views

How is Aperture and Pixel Size accounted for in calculating received power using ray tracing?

NOTE: Deleting the question to rephrase it after continuing to read other responses and toy around with it: I've written a path tracer and am now working on implementing a physically accurate way of ...
1 vote
0 answers
118 views

Directly Sampling an Area Light

So in my path tracer I sample both some bounce ray given an importance function for the current BRDF, and if applicable (reflection is non-specular) I directly sample all light sources (for my ...
0 votes
1 answer
254 views

Albedo image map to color's Light Reflectance Value (LRV)

In many datasets in the literature of both Computer Vision and Computer Graphics there is the albedo map of a scene represented as RGB images, which in principle corresponds to the diffuse reflecting ...
0 votes
1 answer
512 views

Which technique should be used for rendering under water images, Ray tracing or Radiosity?

Rendering is the process of computing a three-dimensional geometric description of a scene into a two-dimensional image representation that looks real. Ray-tracing and Radiosity are two of the most ...
5 votes
3 answers
739 views

What is the purpose of the projected solid angle $dA^\perp$ term in the definition of Radiance?

In the definition of Radiance, which according to PBRT is defined as flux per unit solid angle $d\omega$ per unit projected area $dA^\perp$ $$L_i=\frac{d\Phi}{d\omega\ dA^\perp}$$ My original ...
6 votes
2 answers
300 views

Radiance at a nearly perpendicular angle is almost infinite?

As far as I understand, radiance is a measure of the "intensity" of light in a direction defined as a differential cone . It's measure is Flux per solid angle per projected area. $L = \frac{d\Phi}{d\...
1 vote
1 answer
803 views

Radiosity normal map light baking

I'm trying to implement radiosity normal maps from the old Valve paper: Half-Life® 2 / Valve Source™ Shading.pdf | valvesoftware.com I've tried generating the light maps using Vray and 3dStudio max, ...
6 votes
2 answers
4k views

How to calculate attenuation and radiance in PBR? (point and directional lights)

I would like implement physically based rendering, following this tutorial I was able to find a list of light sources ordered by lumens, but I have no idea how to use it in the calculations. ...
7 votes
1 answer
3k views

What is Radiosity?

After reading a wikipedia article about Global Illumination It mentions a variety of techniques like Ray Tracing, Path Tracing and Ambient Occlusion. One technique it mentions is Radiosity which I don'...
3 votes
2 answers
366 views

How to adapt diffuse/GI light mapper to directional light maps?

I have a working light mapper that captures global illumination. I evaluate a hemisphere when collecting the data and store the result in the texel. However, I want to support directional lightmaps so ...
2 votes
0 answers
591 views

Calculating intensities of Virtual Point Lights in Instant Radiosity from IES lights

Short introduction I created a function that interpolates the IES luminious intensities (candelas) using Hermite interpolation, so in my code all light sources have $I(\theta, \phi)$ function - but ...
6 votes
0 answers
124 views

Form Factors confusion in Radiosity papers

I feel a bit confused about the use of $F_{ij}$ and $F_{ji}$ in Radiosity papers. $F_{ij}$ should be the fraction of energy leaving patch $i$ that arrives at patch $j$. If you take the original ...
4 votes
1 answer
436 views

How to implement Texture Baking?

So currently I want to implement radiosity in my engine. After figuring out the amount of light that bounces between elements/disks/patches (I've been told disks are the best - correct me if I'm wrong)...
9 votes
3 answers
291 views

How does the view-independence of radiosity increase the calculations involved?

In the style of trichoplax' question, I want to talk about yet another Wikipedia article: Radiosity (computer graphics). The article states: Radiosity is viewpoint independent, which increases the ...
5 votes
1 answer
179 views

Are there specific techniques for generating False Radiosity in surfaces?

I thought of this after my radiosity vs ray tracing question. A radiosity algorithm seems to require increased calculations because it's viewpoint independent and therefore, false radiosity was born (...
15 votes
1 answer
12k views

Radiosity VS Ray tracing

Radiosity is basically what allows this: In a tutorial of Cornell University about Radiosity it is mentioned that: A ray-traced version of the image shows only the light reaching the viewer by ...