[Radiance-general] Question about rtrace

[Sheng Yu]

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>.

Thanks in advance!

Yu