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raylistic
01-01-2007, 04:42 PM
Hello everyone,
i got a question. What does input bias mean?
although i manage to get an explanation from maya help, it says:


Opacity Input Bias adjusts the sensitivity of the selected Opacity Input used.



Input values of 0 and 1 always map to the start and end of the opacity curve, although the bias determines where in the curve a value of 0.5 maps. For example if you used Density as an input, and you want the fluid to become opaque at a Density of 0.001, then the Density bias can be used to shift most of the curve into this Density range. Instead of cramming several values at the beginning of the ramp you can use the full range. If the Input Bias is 0.0 then a value of 0.5 maps to the exact middle of the Opacity curve.


But i still cannot understand. Can anyone explain it clearer for me? It would be better if you can explain with some graphics. Thanks alot and happy new year!

Aikiman
01-02-2007, 09:21 PM
Put it this way, 0 (black) to 1 (white) is your normalised ramp you work with most of the time right? If you move the input bias (which determines where the middle of the ramp is, medium grey) up towards white, then you will have medium grey right at the white end, therefore more dark values overall and a very fast falloff to white at one end.

You dont have to use the input bias at all but instead add colour chips to your ramp to get the same effect. However like Maya help has said, its easier just to adjust the input bias rather than shift your pre-existing chips.

And because its the new year, I drew up a diagram for you.

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01-02-2007, 09:21 PM
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