poopinmymouth
06-30-2009, 06:37 AM
Wrote up an advanced guide to controling light, shadows, and specularity. Here's the summary, but check out the full post for all the good stuff. This is all stuff relevant to real life. Obviously on the computer we can have true point lights, or tell lights to ignore falloff, etc. And we can control roughness with a slider, but knowing how the real world works will help you figure out which way to move that slider.
http://mr-chompers.blogspot.com/2009/06/light.html
Unfocused light falls off inverse squarely. Double the distance, 1/4 the brightness. Half the distance, 4x the brightness.
Surface roughness determines how clearly the light source is reflected. Smooth surfaces give you the exact shape, rough surfaces give you a scattered shape.
Apparent size is what's important, not absolute size. A medium source 1 meter away is apparently larger than a giant source 50 meters away.
Apparent size of the light affects the softness of the shadow edge and penumbra. Larger apparent sizes make softer shadows and smoother penumbras, smaller sizes make sharper shadows and harsher penumbras.
Specular reflections do not fall off. They stay the same intensity regardless of distance. Lessening the reflectance of the surface, or making the apparent size of the light larger, is necessary to lessen the specular hotspot's intensity.
Also a few photos from my recent shoots just to get some pictures in here:
http://www.mr-chompers.com/photos/photos-45.jpg http://farm4.static.flickr.com/3317/3668293076_f5531c01bc.jpg (http://www.flickr.com/photos/mr_chompers/3668293076/)
http://mr-chompers.blogspot.com/2009/06/light.html
Unfocused light falls off inverse squarely. Double the distance, 1/4 the brightness. Half the distance, 4x the brightness.
Surface roughness determines how clearly the light source is reflected. Smooth surfaces give you the exact shape, rough surfaces give you a scattered shape.
Apparent size is what's important, not absolute size. A medium source 1 meter away is apparently larger than a giant source 50 meters away.
Apparent size of the light affects the softness of the shadow edge and penumbra. Larger apparent sizes make softer shadows and smoother penumbras, smaller sizes make sharper shadows and harsher penumbras.
Specular reflections do not fall off. They stay the same intensity regardless of distance. Lessening the reflectance of the surface, or making the apparent size of the light larger, is necessary to lessen the specular hotspot's intensity.
Also a few photos from my recent shoots just to get some pictures in here:
http://www.mr-chompers.com/photos/photos-45.jpg http://farm4.static.flickr.com/3317/3668293076_f5531c01bc.jpg (http://www.flickr.com/photos/mr_chompers/3668293076/)