Anti-Aliased Noise

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Anti-Aliased Noise

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The Anti-Aliased Noise is great for generating a fast-performing noise pattern.  

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   The Anti-Aliased Noise (also called the aa noise), is great for situations where you need to generate a noise pattern that doesn't slow down your scene.  The default values go from -0.5 to 0.5.  In order for the noise to stick onto your object, you'll want to use the position (P) plugged into the "pos" input.  If you have deforming geometry, you'll want to use the Rest Position VOP instead of P.  (For more information about texture space and manifolds, visit Shading Techniques I).  

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Main Parameters:


--  The signature defines two things:  What sort of data is coming in?  And what kind of data is going out?  If you plug something in to the "pos" input of the aa noise, it will automatically choose an appropriate input.  The output noise can be either 1D or 3D.  A "1D Noise" means that you're outputting float values. A "3D Noise" means that you're outputting vector values.

3D Position:

--  This parameter defines the texture space that the aa noise lives in.  This correlates with the "pos" input.  For more information about manifolds/texture space, please visit Shading Techniques I.

3D Frequency:

--  The 3D Frequency essentially determines how large the details are in the noise.  The higher the frequency, the smaller the details.  The lower the frequency, the larger the details get.

3D Offset:

--  In practice, the 3D Offset can be used to move the noise values around over time.  It relates to the texture space that you've defined in the 3D Position parameter and acts as an offset to that position.  Again, for more information, please visit the Shading Techniques course.


--  The amplitude will increase the range of values generated by the noise.  By default, the range is -0.5 to 0.5.  If you were to increase the amplitude, it would take your your values further away from 0.  So, the new minimum might be -23 and the new max could go up to 23.  If you're old minimum was at 0 however, then it would not cause things to go negative.  It would, again, push more values further away from 0.


--  Additional detail is added in by layering on additional octaves of noise.  The intensity of each octave is determined by the roughness.  In practice, this adds smaller detail to the larger noise pattern.  Increasing roughness makes each octave more pronounced.  Lower roughness makes each octave less pronounced.

Noise Type:

--  This is the type of noise which is layered on top.  You can choose between Perlin and Simplex.  Both ought to work for most situations, and it's up to you which one you like better.