<p>So I want to path trace a Cornel Box scene, but I don't understand the values given here in section 2 and 3.</p>

<p><a href="http://www.graphics.cornell.edu/online/box/data.html" rel="nofollow noreferrer">Cornell Box Data | Cornell University Program of Computer Graphics</a></p>

<p>No.2 Lists surface reflectances with respect to different wavelengths but I'm not using wavelengths. I thought this was done in spectral path/ray tracing where we are using photometry instead of radiometry.</p>

<p>Similarly No.3 lists Light properties though I don't understand what do the values in the <code>light</code> column (0, 8, 15.6, 18.4) suggest.</p>

<p>I was merely expecting the specular and diffuse reflectivity in all 3 channels for each of the colors red, green and white.</p>

CC BY-SA 4.0
2018-08-14T07:20:53.020Z
You could take a sample at the RED/GREEN/BLUE wavelengths from the table to make a rough RGB for the White/Green/Red materials.
PaulHK
CC BY-SA 4.0
2018-08-14T07:35:09.023Z
@PaulHK - if i understand correct, you mean i should pick 3 wavelengths values from table 2 corresponding to each of the R/G/B. Then i should pick the reflectance values corresponding to them to get my RGB color for each of the `white` `red` and `green` columns?  I could do that but I'm actually writing a general interface using Assimp which loads obj/ply files and reads info from them.  Isn't this approach valid for only this particular case? I couldn't find a .obj format for cornell box. Is there any other way?
gallickgunner
CC BY-SA 4.0
2018-08-14T08:22:52.393Z
It looks like this version of the Cornell box is used to validate spectral tracers and was derived from real world observations
PaulHK
CC BY-SA 4.0
2018-08-14T08:25:59.230Z
would the one from POVRay be any use ? https://github.com/POV-Ray/povray/blob/master/distribution/scenes/radiosity/cornell.pov
PaulHK
CC BY-SA 4.0
2018-08-14T08:29:00.800Z
Hmm, ok are there any other similar models or some other ways I could check first to see If my path tracer is converging correct or not? I was actually interested in comparing my render of cornell box to the iamges provided in that link. But since they are for spectral tracers, is there something similar for non spectral ones?
gallickgunner
CC BY-SA 4.0
2018-08-14T08:38:45.077Z
You could use smallpt as a reference renderer, you can extract the cornell scene used there into your own renderer, their scene is made using spheres only.. > http://www.kevinbeason.com/smallpt/
PaulHK
<pathtracing><physically-based>
Interpreting Cornell Box data for path tracer
gallickgunner
# Interpreting Cornell Box data for path tracer

(Asked by: username_0 on 2018-08-14)

So I want to path trace a Cornel Box scene, but I don't understand the values given here in section 2 and 3.

[Cornell Box Data | Cornell University Program of Computer Graphics](http://www.graphics.cornell.edu/online/box/data.html)

No.2 Lists surface reflectances with respect to different wavelengths but I'm not using wavelengths. I thought this was done in spectral path/ray tracing where we are using photometry instead of radiometry.

Similarly No.3 lists Light properties though I don't understand what do the values in the `light` column (0, 8, 15.6, 18.4) suggest.

I was merely expecting the specular and diffuse reflectivity in all 3 channels for each of the colors red, green and white.

**Tags:** pathtracing, physically-based

> **Comments:**
> **username_1**: You could take a sample at the RED/GREEN/BLUE wavelengths from the table to make a rough RGB for the White/Green/Red materials.  
> **username_0**: @username_1 - if i understand correct, you mean i should pick 3 wavelengths values from table 2 corresponding to each of the R/G/B. Then i should pick the reflectance values corresponding to them to get my RGB color for each of the `white` `red` and `green` columns?  I could do that but I'm actually writing a general interface using Assimp which loads obj/ply files and reads info from them.  Isn't this approach valid for only this particular case? I couldn't find a .obj format for cornell box. Is there any other way?  
> **username_1**: It looks like this version of the Cornell box is used to validate spectral tracers and was derived from real world observations  
> **username_1**: would the one from POVRay be any use ? https://github.com/POV-Ray/povray/blob/master/distribution/scenes/radiosity/cornell.pov  
> **username_0**: Hmm, ok are there any other similar models or some other ways I could check first to see If my path tracer is converging correct or not? I was actually interested in comparing my render of cornell box to the iamges provided in that link. But since they are for spectral tracers, is there something similar for non spectral ones?  
> **username_1**: You could use smallpt as a reference renderer, you can extract the cornell scene used there into your own renderer, their scene is made using spheres only.. > http://www.kevinbeason.com/smallpt/  

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## 0 answers

