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This CHOP allows you to create channels that replicate the values of its parameters through time. Each channel can be named and assigned a different value. The parameter is then evaluated for each frame in the scene file.
This operator can be created from existing channel groups by clicking the name in the Channel Groups list and choosing Motion FX ▸ Create Clip.
Parameters ¶
Data ¶
Show All Parameters
Disabling this toggle simplifies the interface to make the parameters and the values easier to work with. Disable this after the channels have been setup to remove controls that are no longer needed.
Copy to Exports
Copies the animation from the value parameters to the channel export parameters.
Copy from Exports
Copies the animation to the value parameters from the channel export parameters.
Channel Names from Exports
Sets the names of the value parameters to the names of the channel export parameters.
Sort Channels
Sort all the channel by their name.
Reset All Channels
Removes the animation on all the channel values and reset everything to zero.
One Key Per Sample
Instead of evaluating the value parameter every frame, create the channel such that each sample corresponds to a key on the value parameter. This is only meaningful if the value parameter is animated.
Add Node Name Dependencies
If set, this will cause the names specified in the Name parameter to be treated as real parameter paths and have name dependencies built for them. Then if the referenced nodes are renamed, the paths in the Name parameter will update accordingly.
Number of Channels
Number of channels to create.
Name
Name of the channel to create. If the size is greater than 1, then the letter x,y,z, or w is appended to the channel name depending on if it is the first, second, third, or fourth component of the value parameter respectively.
Type
Type of channel to create.
Float
Regular float parameter
Euler Rotation
A quaternion attribute is added to the three generated channels.
Rotate Order
If the type is Euler Rotation, this parameter specifies the order of rotation.
Size
Number of components. If the type is Euler Rotation, this parameter has no effect since 3 components must be generated.
Value
The values of the channels.
Channel ¶
Channel Range
Specifies the range of data to generate.
Use Full Animation Range
All of the animated range.
Use Current Frame
Only the sample at the current frame.
Use Start/End
The range is specified from the Start and End parameters.
Use Value Animation
The range is taken from range of keys available in the evaluated Value parameters.
Ignore Sampling Rate
Ignore the Sampling Rate the Channel Range is set to Use Current Frame. This ensures the sample start time is exactly and the current cook time instead of being restricted to a sample matching the sampling rate.
Start
The start time of the channel range.
End
The end time of the channel range.
Sample Rate
The sample rate of the CHOP.
Extend Left
The left extend condition (before the CHOP’s start).
Extend Right
The right extend condition (after the CHOP’s end).
Default Value
The value to use for the “Default Value” extend condition type.
Common ¶
Some of these parameters may not be available on all CHOP nodes.
Scope
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:
chan2
Matches a single channel name.
chan3 tx ty tz
Matches four channel names, separated by spaces.
chan*
Matches each channel that starts with chan
.
*foot*
Matches each channel that has foot
in it.
t?
The ?
matches a single character. t?
matches two-character channels starting with t.
blend[3-7:2]
Matches number ranges, giving blend3
, blend5
, and blend7
.
blend[2-3,5,13]
Matches channels blend2
, blend3
, blend5
, blend13
.
t[xyz]
[xyz]
matches three characters, giving channels tx
, ty
and tz
.
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.
Units
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).
Note
When you change the Units parameter, the existing parameters are not converted to the new units.
Time Slice
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.
Unload
Causes the memory consumed by a CHOP to be released after it is cooked, and the data passed to the next CHOP.
Export Prefix
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 /obj/geo1/tx
.
Note
You can leave the Export Prefix blank, but then your CHOP track names need to be absolute paths, such as obj:geo1:tx
.
Graph Color
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.
Locals ¶
C
Current channel index.
I
Current index.
NC
Total number of channels.
Examples ¶
ChannelBasic Example for Channel channel node
This is a simple example of using the Channel CHOP along with a Noise CHOP to add some variety to keyframed animation that can still be easily tweaked as keyframe animation. Notice that the object can be manipulated as usual in the viewport transparently. The values will be modified in the Channel CHOP.
See also |