The Noise TOP generates a variety of noise patterns including sparse, alligator and random. It currently runs on the CPU and passes its images to the GPU.
Parameters - Noise Page
/function - The noise function used to generate noise. The functions available are:
- Perlin 2D/3D/4D (GPU) - Perlin noise function calculated on the GPU. Choose between 2, 3, and 4 dimensional functions.
- Simplex 2D/3D/4D (GPU) - Simplex noise function calculated on the GPU. Choose between 2, 3, and 4 dimensional functions.
- Sparse - Produces high quality, continuous noise based on Sparse Convolution.
- Hermite - Quicker than Sparse, but produces lower quality noise.
- Harmonic Summation - Sparse noise with the ability to control the frequency step of the harmonics. Slowest type.
- Random - (White Noise) Every sample is random and unrelated to any other sample. It is the same as "white noise" in audio.
- Alligator - Cell Noise
/seed - Any number, integer or non-integer, which starts the random number generator. Each number gives completely different noise patterns, but with similar characteristics.
/period - The approximate separation between peaks of a noise cycle. It is expressed in Units. Increasing the period stretches the noise pattern out.
Period is the opposite of frequency. If the period is 2 seconds, the base frequency is 0.5 cycles per second, or 0.5Hz for short. Hz refers to Hertz, the electrical and audio engineer of the 19th century, not the car guy.
If the Type is set to Random, setting this to zero will produce completely random noise. Otherwise, the period should be greater than zero.
/harmon - The number of higher frequency components to layer on top of the base frequency. The higher this number, the bumpier the noise will be (as long as roughness is not set to zero). 0 harmonics give the base shape.
/spread - The factor by which the frequency of the harmonics are increased. It is normally 2. A spread of 3 and a base frequency of 0.1Hz will produce harmonics at 0.3Hz, 0.9Hz, 2.7Hz, etc.. This parameter is only valid for the Harmonic Summation type.
/rough - Controls the effect of the higher frequency noise. When roughness is zero, all harmonics above the base frequency have no effect. At one, all harmonics are equal in amplitude to the base frequency. When roughness is between one and zero, the amplitude of higher harmonics drops off exponentially from the base frequency.
The default roughness is 0.5. This means the amplitude of the first harmonic is 0.5 of the base frequency, the second is 0.25, the third is 0.125. The harmonics are added to the base to give the final shape. The Harmonics parameter and the Roughness parameter must both be non-zero to see the harmonic effects.
/exp - Pushes the noise values toward 0, or +1 and -1. (It raises the value to the power of the exponent.) Exponents greater than one will pull the channel toward zero, and powers less than one will pull peaks towards +1 and -1. It is used to reshape the channels.
/amp - Defines the noise value's amplitude (a scale on the values output).
/offset - Defines the midpoint color of the noise pattern, the default is 0.5 grey.
/mono - Toggle color or monochrome noise.
Parameters - Transform Page
/xOrd - The menu attached to this parameter allows you to specify the order in which the transforms will take place. Changing the Transform order will change where things go much the same way as going a block and turning east gets you to a different place than turning east and then going a block.
/rOrd - The rotational matrix presented when you click on this option allows you to set the transform order for the rotations. As with transform order (above), changing the order in which the rotations take place will alter the final position.
Translate / Rotation / Scale / Pivot
/t[xyz] /r[xyz] /s[xyz] /p[xyz] - The Translate, Rotate, Scale and Pivot parameters let you sample in a different part of the 3D noise space. Imagine a different noise value for every XYZ point in space. Normally, the Noise CHOP samples the noise space from (0,0,0) along the X-axis in steps of 2/period.
/tx /ty /tz /rx /ry /rx /sx /sy /sz /px /py /pz
By changing the transform, you are translating, rotating and scaling the line along which the Noise CHOPs samples the noise space. A slight Y-rotation is like walking in a straight path in the mountains, recording your altitude along the way, then re-starting from the same initial location, walking in a slightly different direction. Your altitude starts off being similar but then diverges.
Parameters - Input Page
/uvmultiply - When an input is connected to the Noise TOP, the noise pattern is placed over the input image using UV coordinates. This parameter multiplies the UV coordinates which scales the noise pattern over the input image.
Parameters - Output Page
/inputadd - Adjusts how much of the input image is added to the output.
/noiseadd - Adjusts how much of the noise is added to the output.
Input Multiply Noise
/inputmulnoise - Multiplies the input together with the noise.
/alpha - Sets the alpha channel for the output image.
Parameters - Common Page
Resolution - quickly change the resolution of the TOP's data.
- Input - uses the input's resolution.
- Eighth, Quarter, Half, 2X, 4X, 8X - multiply the input's resolution by that amount.
- Custom Resolution - enables the Custom Res parameter below, giving direct control over res in the X and Y axis.
Custom Res - enabled only when the Resolution parameter is set to Custom Resolution. Some Generators like Constant and Ramp do not use inputs and only use this field to determine their size. The drop down menu on the right provides some commonly used resolutions.
Use Global Resolution Multiplier - Uses the Global Resolution Multiplier found in Edit>Preferences>TOPs. This multiplies all the TOPs resolutions by the set amount. This is handy when working on computers with different hardware specifications. If a project is designed on a desktop workstation with lots of graphics memory, a user on a laptop with only 64MB VRAM can set the Global Resolution Multiplier to a value of half or quarter so it runs at an acceptable speed. By checking this checkbox on, this TOP is affected by the global multiplier.
Aspect Ratio - sets the image aspect ratio allowing any textures to be viewed in any size. Watch for unexpected results when compositing TOPs with different aspect ratios.
- Input - uses the input's aspect ratio.
- Resolution - uses the aspect of the image's defined resolution (ie 512x256 would be 2:1), whereby each pixel is square.
- Custom Aspect Ratio - lets you explicitly define a custom aspect ratio.
Fill Viewer - determine how the TOP image is displayed in the viewer.
- Input - uses the same Fill Viewer settings as it's input.
- Fill - stretches the image to fit the edges of the viewer.
- Fit Horizontal - stretches image to fit viewer horizontally.
- Fit Vertical - stretches image to fit viewer vertically.
- Fit Best - stretches or squashes image so no part of image is cropped.
- Fit Worst - stretches or squashes image so image fills viewer while constraining it's proportions. This often leads to part of image getting cropped by viewer.
- Native Resolution - displays the native resolution of the image in the viewer.
NOTE: To get an understanding of how TOPs works with images, you will want to set this to Native Resolution as you lay down TOPs when starting out. This will let you see what is actually happening without any automatic viewer resizing.
Viewer Smoothness - This controls pixel filtering in the viewers.
- Nearest Pixel - uses nearest pixel or accurate image representation. Images will look jaggy when viewing at any zoom level other than Native Resolution.
- Interpolate Pixels - uses linear filtering between pixels. This is how you get TOP images in viewers to look good at various zoom levels, especially useful when using any Fill Viewer setting other than Native Resolution.
- Mipmap Pixels - uses mipmapfiltering when scaling images. This can be used to reduce artifacts and sparkling in moving/scaling images that have lots of detail. When the input is 32-bit float format nearest filtering will always be used, regardless of what is selected in the menu.
Pixel Format - format used to store data for each channel in the image (ie. R, G, B, and A). Refer to Pixel Formats for more information.
- Input - uses the input's pixel format.
- 8-bit fixed (RGBA) - uses 8-bit integer values for each channel.
- 16-bit float (RGBA) - uses 16-bits per color channel, 64-bits per pixel.
- 32-bit float (RGBA) - uses 32-bits per color channel, 128-bits per pixels.
- 10-bit RGB, 2-bit Alpha, fixed (RGBA) - uses 10-bits per color channel and 2-bits for alpha, 32-bits total per pixel.
- 16-bit fixed (RGBA) - uses 16-bits per color channel, 64-bits total per pixel.
- 11-bit float (RGB), Positive Values Only - A RGB floating point format that has 11 bits for the Red and Green channels, and 10-bits for the Blue Channel, 32-bits total per pixel (therefore the same memory usage as 8-bit RGBA). The Alpha channel in this format will always be 1. Values can go above one, but can't be negative. ie. the range is [0, infinite).
- 8-bit fixed (R) - has 8-bits for the red channel, 8-bits total per pixel.
- 16-bit fixed (R) - has 16-bits for the red channel, 16-bits total per pixel.
- 16-bit float (R) - has 16-bits for the red channel, 16-bits per pixel.
- 32-bit float (R) - has 32-bits for the red channel, 32-bits per pixel.
- 8-bit fixed (RG) - has 8-bits for the red and green channels, 16-bits total per pixel.
- 16-bit fixed (RG) - has 16-bits for the red and green channels, 32-bits total per pixel.
- 16-bit float (RG) - has 16-bits for the red and green channels, 32-bits per pixel.
- 32-bit float (RG) - has 32-bits for the red and green channels, 64-bits per pixel.
- 8-bit fixed (A) - An Alpha only format that has 8-bits per channel, 8-bits per pixel.
- 16-bit float (A) - An Alpha only format that has 16-bits per channel, 16-bits per pixel.
- 32-bit float (A) - An Alpha only format that has 32-bits per channel, 32-bits per pixel.