This CHOP reorganizes a list of channels. It is extremely useful for transforming data received by the Geometry CHOP and Image CHOP into channels containing only one row or column. Data can be easily manipulated, then transformed back if needed.
Chooses the operation shuffle performs.
Swap Channels and Samples
Performs a channel transpose operation, by storing all samples at the same index in the same channel. If 25 channels are in the CHOP with a length of 33 samples, 33 channels will be created with a length of 25.
Sequence Channels By Name
Sequence channels together that share the same alphabetic name, in the order of their number. (ie. chan2, chan3 and chan1 would be sequenced in the order chan1, chan2, chan3).
Sequence All Channels
Sequence all channels in the clip.
Sequence N Channels
Sequence channels in groups of N together. For N=4, channels 0 to 3, 4 to 7, etc. will be sequenced.
Sequence Every Nth Channel
Sequence every Nth channel together. For N=4, channels 0,4,8,.., 1,5,9,…, etc. will be sequenced.
Split All Samples
Split every channel into channels of 1 sample, each containing a different sample from the original channel.
Split N Samples
Split each channel into segments of N samples (specified below).
Split Every Nth Sample
Take every Nth sample from the original to form N new channels.
The new name(s) of the channels after a “Swap Channels and Samples” operation.
The value of N for Sequence Every Nth Channel, Sequence N Channels, Split N Samples and Split Every Nth Sample.
Some of these parameters may not be available on all CHOP nodes.
To determine the channels that are affected, some CHOPs have a scope string. Patterns can be used in Scope, for example
* (match all), and
? (match single character).
The following are examples of possible channel name matching options:
Matches a single channel name.
chan3 tx ty tz
Matches four channel names, separated by spaces.
Matches each channel that starts with
Matches each channel that has
foot in it.
? matches a single character.
t? matches two-character channels starting with t.
Matches number ranges, giving
[xyz]matches three characters, giving channels
Sample Rate Match
The Sample Rate Match options handle cases where multiple input CHOPs’ sample rates are different.
Resample At First Input’s Rate
Use the rate of the first input to resample the others.
Resample At Maximum Rate
Resample to the highest sample rate.
Resample At Minimum Rate
Resample to the lowest sample rate.
Error if Rates Differ
Does not accept conflicting sample rates.
The units of the time parameters.
For example, you can specify the amount of time a lag should last for in seconds (default), frames (at the Houdini FPS), or samples (in the CHOP’s sample rate).
When you change the Units parameter, the existing parameters are not converted to the new units.
Time slicing is a feature that boosts cooking performance and reduces memory usage. Traditionally, CHOPs calculate the channel over its entire frame range. If the channel needs to be evaluated every frame, then cooking the entire range of the channel is unnecessary. It is more efficient to calculate only the fraction of the channel that is needed. This fraction is the Time Slice.
Causes the memory consumed by a CHOP to be released after it is cooked, and the data passed to the next CHOP.
The Export Prefix is prepended to CHOP channel names to determine where to export to.
For example, if the CHOP channel was named
geo1:tx, and the prefix was
/obj, the channel would be exported to
You can leave the Export Prefix blank, but then your CHOP track names need to be absolute paths, such as
Every CHOP has this option. Each CHOP gets a default color assigned to it for display in the graph, but you can override the color with the Graph Color. There are 36 RGB color combinations in the palette.
Graph Color Step
When the graph displays the animation curves, and a CHOP has two or more channels, this defines the difference in color from one channel to the next, giving a rainbow spectrum of colors.