It's not just a matter of grayscale contrast: I want to achieve a visual style that simulates (fakes) natural light. Natural light comes in a wide range of different flavours, and the difference between them can be enormous. The source of all our natural light is the sun, however it takes on different characteristics at different times of day and in different weather conditions, turning this one source of light into essentially many different ones ranging from hard and warm to soft and cool.
In Wings 3D, shadows and color are driven by Spherical Harmonics coordinates. Since I have no idea if Sketchup's rendering engine can do this, I found a workaround by painting my model's surfaces.
I tweaked the ruby script "Color By" by sdmitch, using my personal colour values. The result is a sort of "Cylindical Harmonics" style. My palette is based on the Kelvin Spectrum, which I find pleasant for my eyes.
Here the part of the script that I changed.
def self.direction_color(v)
v.y = v.y > 1.0 ? 1.0 ; v.y
angle=Math.acos(v.y).radians
angle=360.0-angle if v.x < 0.0
### change these test ranges and/or color to suit...
case angle
when 11.25...33.75;color=[255,189,124]; #2000 K°
when 33.75...56.25;color=[255,217,181];
when 56.25...78.75;color=[254,227,203];
when 78.75...101.25;color=[253,237,225];
when 101.25...123.75;color=[249,237,232];
when 123.75...146.25;color=[245,238,239];
when 146.25...168.75;color=[238,238,247];
when 168.75...191.25;color=[232,237,254];
when 191.25...213.75;color=[223,232,254];
when 213.75...236.25;color=[214,227,255];
when 236.25...258.75;color=[201,219,255];
when 258.75...281.25;color=[191,212,255];
when 281.25...303.75;color=[181,206,255];
when 303.75...326.25;color=[166,197,255];
when 326.25...348.75;color=[151,187,255]; #8000 K°
else color=[255,255,255];
Now, it would be nice to drive this with the sun position, and have an imput panel where you can set 2 main colors and let the script generate the gradient between them. In this way we could easlily fake the light of midday sunshine, late afernoon, sunset, dusk and so on.
Anybody who can help is welcome!
[image: uYhU_skechup-test-1.gif]
