Slope TOP
Summary
The Slope TOP generates pixels that represent the difference between its value and its neighbouring pixels' values. Given that pixel values are between 0 and 1, the value of .5 means the neighbor's values are the same as the pixel's value. Values output in the red channel that are above .5 indicate the values are increasing lefttoright. Values output in the blue channel that are above .5 indicate the values are increasing bottomtotop.
Parameters  Slope Page
Red red
 ⊞  Select which method is used to calculate the slope of the Red channel. Horizontal and Vertical options let you calculate the slope by sampling points horizontally or vertically.
 Horizontal Luminance
hluminance
 Uses the luminance values of the image to calculate slope.
 Horizontal Red
hred
 Uses the red channel of the image to calculate slope.
 Horizontal Green
hgreen
 Uses the green channel of the image to calculate slope.
 Horizontal Blue
hblue
 Uses the blue channel of the image to calculate slope.
 Horizontal Alpha
halpha
 Uses the alpha channel of the image to calculate slope.
 Horizontal RGB Average
hrgbaverage
 Uses the combined RGB average of the image to calculate slope.
 Horizontal RGBA Average
haverage
 Uses the combined RGBA average of the image to calculate slope.
 Vertical Luminance
vluminance
 Uses the luminance values of the image to calculate slope.
 Vertical Red
vred
 Uses the red channel of the image to calculate slope.
 Vertical Green
vgreen
 Uses the green channel of the image to calculate slope.
 Vertical Blue
vblue
 Uses the blue channel of the image to calculate slope.
 Vertical Alpha
valpha
 Uses the alpha channel of the image to calculate slope.
 Vertical RGB Average
vrgbaverage
 Uses the combined RGB average of the image to calculate slope.
 Vertical RGBA Average
vaverage
 Uses the combined RGBA average of the image to calculate slope.
 Neutral
neutral
 Sets that channel to the Zero Point.
 One
one
 Sets that channel to one.
 Zero
zero
 Sets that channel to zero.
Green green
 ⊞  Select which method is used to calulate the slope of the Green channel. Horizontal and Vertical options let you calculate the slope by sampling points horizontally or vertically.
 Horizontal Luminance
hluminance
 Uses the luminance values of the image to calculate slope.
 Horizontal Red
hred
 Uses the red channel of the image to calculate slope.
 Horizontal Green
hgreen
 Uses the green channel of the image to calculate slope.
 Horizontal Blue
hblue
 Uses the blue channel of the image to calculate slope.
 Horizontal Alpha
halpha
 Uses the alpha channel of the image to calculate slope.
 Horizontal RGB Average
hrgbaverage
 Uses the combined RGB average of the image to calculate slope.
 Horizontal RGBA Average
haverage
 Uses the combined RGBA average of the image to calculate slope.
 Vertical Luminance
vluminance
 Uses the luminance values of the image to calculate slope.
 Vertical Red
vred
 Uses the red channel of the image to calculate slope.
 Vertical Green
vgreen
 Uses the green channel of the image to calculate slope.
 Vertical Blue
vblue
 Uses the blue channel of the image to calculate slope.
 Vertical Alpha
valpha
 Uses the alpha channel of the image to calculate slope.
 Vertical RGB Average
vrgbaverage
 Uses the combined RGB average of the image to calculate slope.
 Vertical RGBA Average
vaverage
 Uses the combined RGBA average of the image to calculate slope.
 Neutral
neutral
 Sets that channel to the Zero Point.
 One
one
 Sets that channel to one.
 Zero
zero
 Sets that channel to zero.
Blue blue
 ⊞  Select which method is used to calulate the slope of the Blue channel. Horizontal and Vertical options let you calculate the slope by sampling points horizontally or vertically.
 Horizontal Luminance
hluminance
 Uses the luminance values of the image to calculate slope.
 Horizontal Red
hred
 Uses the red channel of the image to calculate slope.
 Horizontal Green
hgreen
 Uses the green channel of the image to calculate slope.
 Horizontal Blue
hblue
 Uses the blue channel of the image to calculate slope.
 Horizontal Alpha
halpha
 Uses the alpha channel of the image to calculate slope.
 Horizontal RGB Average
hrgbaverage
 Uses the combined RGB average of the image to calculate slope.
 Horizontal RGBA Average
haverage
 Uses the combined RGBA average of the image to calculate slope.
 Vertical Luminance
vluminance
 Uses the luminance values of the image to calculate slope.
 Vertical Red
vred
 Uses the red channel of the image to calculate slope.
 Vertical Green
vgreen
 Uses the green channel of the image to calculate slope.
 Vertical Blue
vblue
 Uses the blue channel of the image to calculate slope.
 Vertical Alpha
valpha
 Uses the alpha channel of the image to calculate slope.
 Vertical RGB Average
vrgbaverage
 Uses the combined RGB average of the image to calculate slope.
 Vertical RGBA Average
vaverage
 Uses the combined RGBA average of the image to calculate slope.
 Neutral
neutral
 Sets that channel to the Zero Point.
 One
one
 Sets that channel to one.
 Zero
zero
 Sets that channel to zero.
Alpha alpha
 ⊞  Select which method is used to calulate the slope of the Alpha channel. Horizontal and Vertical options let you calculate the slope by sampling points horizontally or vertically.
 Horizontal Luminance
hluminance
 Uses the luminance values of the image to calculate slope.
 Horizontal Red
hred
 Uses the red channel of the image to calculate slope.
 Horizontal Green
hgreen
 Uses the green channel of the image to calculate slope.
 Horizontal Blue
hblue
 Uses the blue channel of the image to calculate slope.
 Horizontal Alpha
halpha
 Uses the alpha channel of the image to calculate slope.
 Horizontal RGB Average
hrgbaverage
 Uses the combined RGB average of the image to calculate slope.
 Horizontal RGBA Average
haverage
 Uses the combined RGBA average of the image to calculate slope.
 Vertical Luminance
vluminance
 Uses the luminance values of the image to calculate slope.
 Vertical Red
vred
 Uses the red channel of the image to calculate slope.
 Vertical Green
vgreen
 Uses the green channel of the image to calculate slope.
 Vertical Blue
vblue
 Uses the blue channel of the image to calculate slope.
 Vertical Alpha
valpha
 Uses the alpha channel of the image to calculate slope.
 Vertical RGB Average
vrgbaverage
 Uses the combined RGB average of the image to calculate slope.
 Vertical RGBA Average
vaverage
 Uses the combined RGBA average of the image to calculate slope.
 Neutral
neutral
 Sets that channel to the Zero Point.
 One
one
 Sets that channel to one.
 Zero
zero
 Sets that channel to zero.
Method method
 ⊞  Determines what pixels to use when calculating the slope at each pixel in the image.
 Use Previous And Current
prevcur
 Uses the previous and current pixels for slope calculation.
 Use Current And Next
curnext
 Uses the current and next pixels for slope calculation.
 Use Previous And Next
prevnext
 Uses the previous and next pixels for slope calculation.
Zero Point zeropoint
 Sets the value that is considered zero slope, similar to a midpoint.
Strength strength
 Set the strength of the output using this multiplier. Higher values result in higher slope values.
Sample Step offset
 ⊞  When sampling the image, this determines the distance from each pixel to the sample pixel. When units are set to pixels, it is the number of pixels away from the current pixel which is sampled to find edges. A Sample Step of 3 would sample pixels 3 pixels away to look for edges.
offset1

offset2
Sample Step Unit offsetunit
 ⊞ 
Parameters  Common Page
Output Resolution outputresolution
 ⊞  quickly change the resolution of the TOP's data.
 Use Input
useinput
 Uses the input's resolution.
 Eighth
eighth
 Multiply the input's resolution by that amount.
 Quarter
quarter
 Multiply the input's resolution by that amount.
 Half
half
 Multiply the input's resolution by that amount.
 2X
2x
 Multiply the input's resolution by that amount.
 4X
4x
 Multiply the input's resolution by that amount.
 8X
8x
 Multiply the input's resolution by that amount.
 Fit Resolution
fit
 Multiply the input's resolution by that amount.
 Limit Resolution
limit
 Multiply the input's resolution by that amount.
 Custom Resolution
custom
 Enables the Resolution parameter below, giving direct control over width and height.
Resolution resolution
 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.
Resolution Menu resmenu

Use Global Res Multiplier resmult
 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.
Output Aspect outputaspect
 ⊞  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. (You can define images with nonsquare pixels using xres, yres, aspectx, aspecty where xres/yres != aspectx/aspecty.)
 Use Input
useinput
 Uses the input's aspect ratio.
 Resolution
resolution
 Uses the aspect of the image's defined resolution (ie 512x256 would be 2:1), whereby each pixel is square.
 Custom Aspect
custom
 Lets you explicitly define a custom aspect ratio in the Aspect parameter below.
Aspect aspect
 ⊞  Use when Output Aspect parameter is set to Custom Aspect.
aspect1

aspect2
Aspect Menu armenu

Input Smoothness inputfiltertype
 ⊞  This controls pixel filtering on the input image of the TOP.
 Nearest Pixel
nearest
 Uses nearest pixel or accurate image representation. Images will look jaggy when viewing at any zoom level other than Native Resolution.
 Interpolate Pixels
linear
 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
mipmap
 Uses mipmap filtering when scaling images. This can be used to reduce artifacts and sparkling in moving/scaling images that have lots of detail.
Fill Viewer fillmode
 ⊞  Determine how the TOP image is displayed in the viewer.
NOTE:To get an understanding of how TOPs work 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.
 Use Input
useinput
 Uses the same Fill Viewer settings as it's input.
 Fill
fill
 Stretches the image to fit the edges of the viewer.
 Fit Horizontal
width
 Stretches image to fit viewer horizontally.
 Fit Vertical
height
 Stretches image to fit viewer vertically.
 Fit Best
best
 Stretches or squashes image so no part of image is cropped.
 Fit Outside
outside
 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
nativeres
 Displays the native resolution of the image in the viewer.
Viewer Smoothness filtertype
 ⊞  This controls pixel filtering in the viewers.
 Nearest Pixel
nearest
 Uses nearest pixel or accurate image representation. Images will look jaggy when viewing at any zoom level other than Native Resolution.
 Interpolate Pixels
linear
 Uses linear filtering between pixels. Use this to 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
mipmap
 Uses mipmap filtering when scaling images. This can be used to reduce artifacts and sparkling in moving/scaling images that have lots of detail.
Passes npasses
 Duplicates the operation of the TOP the specified number of times. Making this larger than 1 is essentially the same as taking the output from each pass, and passing it into the first input of the node and repeating the process. Other inputs and parameters remain the same for each pass.
Channel Mask chanmask
 Allows you to choose which channels (R, G, B, or A) the TOP will operate on. All channels are selected by default.
Pixel Format 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.
 Use Input
useinput
 Uses the input's pixel format.
 8bit fixed (RGBA)
rgba8fixed
 Uses 8bit integer values for each channel.
 sRGB 8bit fixed (RGBA)
srgba8fixed
 Uses 8bit integer values for each channel and stores color in sRGB colorspace.
 16bit float (RGBA)
rgba16float
 Uses 16bits per color channel, 64bits per pixel.
 32bit float (RGBA)
rgba32float
 Uses 32bits per color channel, 128bits per pixels.
 10bit RGB, 2bit Alpha, fixed (RGBA)
rgb10a2fixed
 Uses 10bits per color channel and 2bits for alpha, 32bits total per pixel.
 16bit fixed (RGBA)
rgba16fixed
 Uses 16bits per color channel, 64bits total per pixel.
 11bit float (RGB), Positive Values Only
rgba11float
 A RGB floating point format that has 11 bits for the Red and Green channels, and 10bits for the Blue Channel, 32bits total per pixel (therefore the same memory usage as 8bit 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).
 16bit float (RGB)
rgb16float

 32bit float (RGB)
rgb32float

 8bit fixed (Mono)
mono8fixed
 Single channel, where RGB will all have the same value, and Alpha will be 1.0. 8bits per pixel.
 16bit fixed (Mono)
mono16fixed
 Single channel, where RGB will all have the same value, and Alpha will be 1.0. 16bits per pixel.
 16bit float (Mono)
mono16float
 Single channel, where RGB will all have the same value, and Alpha will be 1.0. 16bits per pixel.
 32bit float (Mono)
mono32float
 Single channel, where RGB will all have the same value, and Alpha will be 1.0. 32bits per pixel.
 8bit fixed (RG)
rg8fixed
 A 2 channel format, R and G have values, while B is 0 always and Alpha is 1.0. 8bits per channel, 16bits total per pixel.
 16bit fixed (RG)
rg16fixed
 A 2 channel format, R and G have values, while B is 0 always and Alpha is 1.0. 16bits per channel, 32bits total per pixel.
 16bit float (RG)
rg16float
 A 2 channel format, R and G have values, while B is 0 always and Alpha is 1.0. 16bits per channel, 32bits total per pixel.
 32bit float (RG)
rg32float
 A 2 channel format, R and G have values, while B is 0 always and Alpha is 1.0. 32bits per channel, 64bits total per pixel.
 8bit fixed (A)
a8fixed
 An Alpha only format that has 8bits per channel, 8bits per pixel.
 16bit fixed (A)
a16fixed
 An Alpha only format that has 16bits per channel, 16bits per pixel.
 16bit float (A)
a16float
 An Alpha only format that has 16bits per channel, 16bits per pixel.
 32bit float (A)
a32float
 An Alpha only format that has 32bits per channel, 32bits per pixel.
 8bit fixed (Mono+Alpha)
monoalpha8fixed
 A 2 channel format, one value for RGB and one value for Alpha. 8bits per channel, 16bits per pixel.
 16bit fixed (Mono+Alpha)
monoalpha16fixed
 A 2 channel format, one value for RGB and one value for Alpha. 16bits per channel, 32bits per pixel.
 16bit float (Mono+Alpha)
monoalpha16float
 A 2 channel format, one value for RGB and one value for Alpha. 16bits per channel, 32bits per pixel.
 32bit float (Mono+Alpha)
monoalpha32float
 A 2 channel format, one value for RGB and one value for Alpha. 32bits per channel, 64bits per pixel.
TOPs 

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An Operator Family that creates, composites and modifies images, and reads/writes images and movies to/from files and the network. TOPs run on the graphics card's GPU.
Each SOP has a list of Points. Each point has an XYZ 3D position value plus other optional attributes. Each polygon Primitive is defined by a vertex list, which is list of point numbers.
The width and height of an image in pixels. Most TOPs, like the Movie File In TOP can set the image resolution. See Aspect Ratio for the width/height ratio of an image, taking into account nonsquare pixels.
The viewer of a node can be (1) the interior of a node (the Node Viewer), (2) a floating window (RMB>View... on node), or (3) a Pane that graphically shows the results of an operator.