[Radiance-general] Question about rtrace

[Thomas Bleicher]

On 29 Jan 2009, at 07:32, Sheng Yu wrote:

> Hi,
>
> I am confused with what rtrace does. Does it just sample one ray at
> the input point <xorg yorg zorg> in the direction <xdir ydir zdir> and
> calculate the light gained from that direction, or it will sample many
> rays through the hemisphere and calculate all the light that reaches
> the hemisphere? In the second case, the input direction <xdir ydir
> zdir> is the normal at point <xorg yorg zorg>.

See the man page, '-I' (uppercase 'i') option:

-I 	Boolean switch to compute irradiance  rather  than  radiance,
         with  the  input  origin and direction interpreted instead as
         measurement point and orientation.


Regards,
Thomas