[Radiance-general] incident ray angles

[Greg Ward]

Have you investigated the program "rsensor"?  It should be able to handle any distribution you like.

By default, the -I option of rtrace gives you a cosine-weighted irradiance value.  If you need to add a cut-off, you can compute -I in the apex of a black cone of the appropriate size.

-Greg

> From: Jia Hu <hujia06 at gmail.com>
> Date: February 20, 2014 8:45:33 AM GMT+01:00
> 
> Hello,
> 
> I have a sensor and the sensor has different readings according to angle between incident ray and normal. Theoretically, this readings should be [cos(theta)*value of incident rays] hitting the sensor point (theta = angle between ray hitting the surface and sensor normal).  However,t our sensor is not this  relationship and I have to adjust the simualtion results to fit the actual sensor readings.
> 
> one of the methods I can think of is to get directions of all the incident rays hitting the sensor point and then calculate all the angles between incident rays and sensor normal, and adjust the radiance values before using rtrac to calculate the actual illuminance values.  Is that feasible?   I notice there is a "t" option in rtrace, but it will return all the rays, not just rays hitting the sensor points. 
> Radiance traces only 1 ray from the sensor points or sample a number of rays from sensor point? (my understaning was that rtrace first traces a number of rays to check DIRECT light source and get the results, and then traces a SINGLE ray following the sensor normal and then sampling more when hitting a surface? if in this case, how can I determine the anges of direct and indirect rays?) 
> 
> Thanks,
> 
> jia
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