9.5.2

822 • CHAPTER 18
MATERIAL EDITOR • 823
The Blur Scale ne-tunes the strength of the MIP/SAT mapping.
MIP and SAT mapping only approximate the optimum computation, since a precise computation would
increase the render time greatly. SAT mapping is more accurate than MIP mapping. But sometimes
these approximations can make a texture too blurred or too sharp. So the Blur Offset and Blur Scale
options enable you to blur or sharpen the mapping. Blur Offset softens a texture. Blur Scale ne-tunes
the strength of the MIP/SAT mapping. A positive value increases the blur; a negative value weakens it.
A strong value blurs detail but helps prevent ickering during animation. A weaker value brings out
more detail but, increases the risk of ickering.
Mix Mode, Mix Strength
Use these parameters to mix the color and texture panes using one of four modes. The default mode
for all channels is Normal, except for the Environment page, which uses Multiply as the default mode.
Not all channels have Mix settings. If you load a texture or a 2D shader, it is placed on a layer above
the color (i.e. the texture is placed on top of the color). Mix Strength denes the mixing proportion
between the texture and color panes.
Normal
In normal mode, the Mix Strength sets the opacity of the texture. If the value is set to 100%, you’ll
see the texture only (remember, the texture is the top layer, so if it is opaque you won’t see the color
underneath). If the value is set to 70%, the result is 70% of the texture and 30% of the color.
For example, if a texture pixel of RGB 255/0/0 (red) is used with a color value of RGB 255/255/0 (yellow)
with the Mix Strength set to 50%, the resultant color is 255/128/0 (orange).
Add
The texture’s RGB value is added to the color’s RGB value. Color channel values cannot exceed the
maximum of RGB 255. So if a texture pixel of RGB 0/255/255 (cyan) is added to a color value of 255/
255/0 (yellow), the result is 255/255/255 (white).
Subtract
The color’s RGB value is subtracted from the texture’s RGB value. Thus if a texture pixel is RGB 255/
255/255 (white) and the color value is 255/0/0 (red), subtracting with Mix Strength set to 100% gives
the result 0/255/255 (cyan).