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Light pipes

Posted: Mon May 16, 2011 9:34 pm
by earache
Has anyone done any accurate light pipe renderings? I'm fine tuning a light pipe design and was looking to Maxwell to help me out. I grabbed the Transparent Acrylic material out of the MXM library and it appears to be fairly accurate as far as light transmission, although I'm not 100% confident that it's modeling correctly. Any other recommendations for which MXM to use? Ultimately I will be molding the light pipe out of acrylic, so it would be great to get an accurate rendering to prove out the design. Thanks for any ideas.

Re: Light pipes

Posted: Mon May 16, 2011 9:40 pm
by Half Life
You could use a complex IOR for the specific type of acrylic you are using or get a correct Nd for the specific type of acrylic from here:

http://www.luxpop.com/

or here:

http://refractiveindex.info/

Just use 589nm for the wavelength and input that into Maxwell... this will give the most accurate results you can have without a complex IOR file.

Best,
Jason.

Re: Light pipes

Posted: Mon May 16, 2011 10:50 pm
by David Solito
thanks 4 the links.
Except nd and K are the other value usable?

Re: Light pipes

Posted: Mon May 16, 2011 11:02 pm
by Half Life
You could probably use some of them for things like Reflectance 0/90, transmittance and attenuation but the problem I've found is the terminology often doesn't match and so it gets a bit hard to know how these things translate.

For instance I've had a hard time just converting one xyz colorspace data set to Maxwell XYZ colorspace -- which I eventually gave up on and just converted to RGB, this is where my RAL lines come from... but my point is sometimes the translation process is not seamless.

Of course it doesn't help that I'm not terribly educated on the Math side -- the result of a lifetime of studying paint, paper, canvas and brushes I'm afraid :wink:

If the manual contained some formula or THINK! had some converters then this might be a more realistic possibility :D

Best,
Jason.

Re: Light pipes

Posted: Tue May 17, 2011 11:19 am
by adman
removed