So we can now write:
The rendering equation is
I(x,x') = g(x,x') \left[ \epsilon(x,x') + \int_{S} \rho(x,x',x'') I(x',x'') dx'' \right]where:
I(x,x') is the related to the intensity of light passing from
point x' to point xg(x,x') is a “geometry” term
\epsilon(x,x') is related to the intensity of emitted light from x' to x
\rho(x,x',x'') is related to the intensity of light scattered from x'' to x
by a patch of surface at x'
Markdown:
The rendering equation is
$$
I(x,x') = g(x,x') \left[ \epsilon(x,x') + \int_{S} \rho(x,x',x'') I(x',x'') dx'' \right]
$$
where:
$I(x,x')$ is the related to the intensity of light passing from
point $x'$ to point $x$
$g(x,x')$ is a “geometry” term
$\epsilon(x,x')$ is related to the intensity of emitted light from $x'$ to $x$
$\rho(x,x',x'')$ is related to the intensity of light scattered from $x''$ to $x$
by a patch of surface at $x'$
Thank you to Dan Fuller of LBNL.