ideal diffusely reflecting surface

[Or Yogev]

Hello, 

I am posting this message again since I got no response last time. Can someone please help me on that issue. 

I am trying to define an ideal diffusely reflecting surface, one in which the reflected ray has a full range of angles with equal probability (as oppose to specular reflecting surface like mirror). Is it possible define such an optical characteristic using one of the surface parameters. 

Thanks, 

Or

[Manuel J. Blanco]

Dear Or,

You can approximate a diffuse reflecting surface by using the material plug-in named "Specular_Standard_Material" and setting the parameter m_sigmaSlope equal to 785.3981, which is Pi divided by 4 in mrad, and by setting the parameter m_reflectivity to your preferred value between 0 and 1.

I have tested qualitatively this approximation using the attached Tonatiuh file to simulate the reflective behaviour of a flat square diffuse reflecting surface when subjected to incident solar radiation, and as it can bee seen from the attached Tonatiuh scereen capture the rays reflected by the surface seem to be scattered in all directions.

If you could analyse quantitatively this preliminary qualitative result to convince yourself that the approach I am suggesting to simulate a diffuse reflecting surface is correct and share the results with all of us it will be great. It will be useful to test if the behaviour of the surface is independent of the direction of the sunlight as I expect it to be.

Best regards, 

[Manuel J. Blanco]

Here it is the figure I was referring in my previous post. For some reason the system did not allow me to attach it the my original post.

[Or Yogev]

Dear Manuel, 

I believe there is a bug in the program. As you can from the figure below in this simulation rays are reflected from the heliostat field into an opaque cylinder with high reflectivity in which the sigma_slope was set to pi/4 mrad as indicated by your previous email (i.e to mimic a diffusive material). However as you can see some of the reflected rays are actually "escaping" though the cylinder circumference. This "phenomena"  gets eliminated once the sigma_slope is set to a low value (i.e. the cylinder is behaving more like a specular material rather the diffusive one). 

Thanks, 

Or

--
You received this message because you are subscribed to the Google Groups "Tonatiuh - Monte Carlo ray tracer for the optical simulation of CSP systems." group.
To unsubscribe from this group and stop receiving emails from it, send an email to tonatiuh-raytra...@googlegroups.com.
To post to this group, send email to tonatiuh-...@googlegroups.com.
Visit this group at http://groups.google.com/group/tonatiuh-raytracer?hl=en.
For more options, visit https://groups.google.com/groups/opt_out.
 
 

--
Or Yogev

[yanir.a...@gmail.com]

Or hi

Did you found a solution for your request within the Tonatiuh software or by other?

I also try to build a simulation with diffuse material.

Regards

Yanir

To unsubscribe from this group and stop receiving emails from it, send an email to tonatiuh-raytracer+unsub...@googlegroups.com.

To post to this group, send email to tonatiuh-...@googlegroups.com.
Visit this group at http://groups.google.com/group/tonatiuh-raytracer?hl=en.
For more options, visit https://groups.google.com/groups/opt_out.
 
 

--
Or Yogev