This extreme telephoto shot, with a 10 degree field of view, gives a good
view of the Shadow Squares. These are modeled using just
simple polygons, shaded a
constant color with the standard matte surface shader. This is consistent
with the description in Ringworld of the Shadow Squares being
This is my second attempt at a Sun. My first Sun was a point light
source inside a sphere. The sphere was transparent to the light but
had a constant shader that made it visible when you looked at it.
It looked OK, but didn't produce soft shadows.
The current Sun is an area light source. This gives soft shadows
at the expense of much longer rendering times. The right way to do
this is to build the day and night into the ring surface shader
itself. Then a simple point light could serve as the Sun.
A second sphere surrounds the sun sphere and is shaded with a glow
shader. This produces a reasonable corona effect. The Sun could
be much more detailed, if I felt like getting into it.
The star background uses a noise based starfield shader written by
Larry Gritz. Alas, it doesn't animate at all, so I need to start
over from scratch if I want to animage the Ringworld.