material definition

Hi,

I am planning to do a great deal of simulations of an interior space, with
different combinations of materials ( such as different kinds of paint,
plaster, wood, stone, ceramic tile, and carpet) , so I wonder if there are
some well defined material libraries for Radiance that I can refer to, or
how to make a proper material defination by myself if no such material
library exist.

thanks a lot.

Yours,
Huang

Hi,

this is quite a FAQ. There are libraries available, however, if you exactly know the material you want to simulate, it is often desireable to use a real sample and not a "generic" material description that may vary from the one you will use. Still these libraries are valuable, as they give an idea of how it might look like, and some are simply measured data files. The most popular material library is the one that comes with Radiance, it is called materials.rad and you find it in the lib directory. There are great libraries on the mgf-website, go to radsite.lbl.gov, and take a look at the mgf pages. You can use mgf2rad to convert these libraries to the material format that is used by radiance.

Finally, there are a lot of ways to generate your own material descriptions. You should really take a look at the book "rendering with radiance". There are different methods, from "guess and compare" to measurements with special equipment. I have used "calibrated" photographs, with the help of the mabbethcal utility.

CU Lars.