The Speed CHOP converts speed (units per second) to distance (units) over a time range. More generally, you give it a rate (the CHOP input) and it outputs a cumulative value. For example, the Speed CHOP converts rotation rate (rotations per second) into the number of rotation turns. ( Math-heads recognize this as an 'integral', which calculates the area under a curve. The curve is the incoming channel values over a time range, the output is the area.)
If you send a Constant CHOP channel that has value 1 into the Speed CHOP, then the Speed CHOP output will increase by 1 every second. If you feed it -2, it will decrease by 2 every second, and if you feed it 0, the output will not change. Use a Trail CHOP to see its results. You can reset the Speed CHOP to 0 by pressing the Reset parameter, or by sending in a channel (whose value is greater than 0) into the second input.
The first input contains the channels to be 'integrated'. By default, the Speed CHOP is time-sliced, so it keeps adding/subtracting to the output each frame it cooks. If you turn off its Time Slice parameter and send it a CHOP with a fixed frame range (like a default Noise CHOP), you can see the cumulative value starting from 0.
The output is calculated by adding the input's channel values for every sample, divided by the samples per second of the Speed CHOP (typically 60), starting with the sample at the Start index. Negative input values reduce the output, positive values increase it. The cumulative values are put in the output channels.
When the CHOP is reset, its output can be set to any value via the Reset Value parameter.
When the second input is used to reset the output, where the second input is greater than 0, the area is reset and held to the reset value. For example, a Wave CHOP (which is negative half the time) when passed into the second input causes the output to be reset for half a cycle.
Parameters - Speed Page
order - ⊞ - Determines the order of the integral to use. If the input is a velocity, a First Order integral will return the position. If the input is an acceleration, a Second Order integral will return the position, and a First Order integral will return the velocity.
constant1 - Constant to add to the entire result after integrating once.
constant2 - Constant to add to the entire result after integrating twice.
constant3 - Constant to add to the entire result after integrating three times.
limittype - ⊞ - The type of limit function to use:
off- Do not limit the values.
clamp- Simply cut the channel value off if it is out of the Maximum/Minimum range, and replace it with the Maximum or Minimum limit value.
loop- Continue the channel at the other end of the interval.
zigzag- Mirror the values back inside the interval.
min - The minimum value the output channel can have.
max - The maximum value the output channel can have.
resetcondition - ⊞ - This menu determines how the Reset input triggers a reset of the channel(s).
- Off to On
offtoon- Channels are reset when the Reset input goes off to on.
- While On
on- Channels are reset when the Reset input goes on. The channel will hold the reset value until the input turns off.
- On to Off
ontooff- Channels are reset when the Reset input goes on to off.
- While Off
off- Channels are reset when the Reset input goes off. The channel will hold the reset value until the input turns on.
resetvalue - The channel(s) is set to this value when reset.
reset - This button resets the channel(s) to the Reset Value.
Parameters - Common Page
timeslice - Turning this on forces the channels to be "Time Sliced". A Time Slice is the time between the last cook frame and the current cook frame.
scope - To determine which channels get affected, some CHOPs use a Scope string on the Common page.
Sample Rate Match
srselect - ⊞ - Handle cases where multiple input CHOPs' sample rates are different. When Resampling occurs, the curves are interpolated according to the Interpolation Method Option, or "Linear" if the Interpolate Options are not available.
- Resample At First Input's Rate
first- Use rate of first input to resample others.
- Resample At Maximum Rate
max- Resample to the highest sample rate.
- Resample At Minimum Rate
min- Resample to the lowest sample rate.
- Error If Rates Differ
err- Doesn't accept conflicting sample rates.
exportmethod - ⊞ - This will determine how to connect the CHOP channel to the parameter. Refer to the Export article for more information.
- DAT Table by Index
datindex- Uses the docked DAT table and references the channel via the index of the channel in the CHOP.
- DAT Table by Name
datname- Uses the docked DAT table and references the channel via the name of the channel in the CHOP.
- Channel Name is Path:Parameter
autoname- The channel is the full destination of where to export to, such has
autoexportroot - This path points to the root node where all of the paths that exporting by Channel Name is Path:Parameter are relative to.
exporttable - The DAT used to hold the export information when using the DAT Table Export Methods (See above).
- Input 0 -
- Input 1 -
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A Time Slice is the time from the last cook frame to the current cook frame. In CHOPs it is the set of short channels that only contain the CHOP channels' samples between the last and the current cook frame.
To pulse a parameter is to send it a signal from a CHOP or python or a mouse click that causes a new action to occur immediately. A pulse from a CHOP is typically a 0 to 1 to 0 signal in a channel, and a pulse via python is via a
.pulse() call on a pulse-type parameter, such as Reset in a Speed CHOP.
A parameter in most CHOPs that restricts which channels of that CHOP will be affected. Normally all channels of a CHOP are affected by the operator.
samples-per-second of a CHOP. Each CHOP in your network has a sample rate, whether it is used or not. The overall timeline has a "frame rate", which is the number of animation frames per second, generally your monitor display frequency.
Exporting is the connection of CHOP channels to parameters of operators. The output of each exporting CHOP is one or more channels, active only while the CHOP Viewer is on. The current value of a channel can be exported to a parameter of any operator, overriding that parameter's value. See Parameter.
Parameters in TouchDesigner are an operator's settings (numbers, menus, flags, strings, paths) which the user can alter. Parameters for any operator can be opened by right-clicking on the operator and selecting "Parameters..." A currently selected operator's parameters can be viewed in a Network Editor by pressing the keyboard shortcut 'p'.