[Radiance-general] Color reflectance values and materials..

[Lars O. Grobe]

> Anyway, as a start it might be worth thinking about a central web based material depository where we all can share our own creations. The display format can be a simple list with mat, cal, pic files and a little preview.
> Anyone interested in starting that? 
>   
Maybe one should first consider a database of measured values. Based on 
this, one could implement a material editor that could query that 
database and give a radiance material definition as a result. The 
advantage is that I could compile the material data available into a 
description fitting the needs of my specific application. It is 
important to keep in mind that our measurements and simulations not only 
have a degree of accuracy but also a scale. A material for a wall of 
bricks is not only depending on exterior influences (dirt, humidity, 
vegetation) but also on the scale we look at it - from far a way it will 
be sufficient to define it as one uniform color, sampled e.g. over 
2mx2m, from a close point of view I would want to have a brick texture 
including the different colors of brick and mortar, and for a detail 
view I would need the color and structure of only the brick itself, as 
the mortar would be a different material. Just one very simple example, 
other materials are much more difficult. Still sharing the measured 
values (including very detailed descriptions of object and set-up) would 
be very useful for the secondary materials, those that a simulation not 
really focuses on and could be approximated. Think I would be interested 
in contributing.

CU Lars.