Delete channel node

Removes channels coming from its input.

All

Parameters

Example files

See also: Copy

The Delete CHOP removes channels coming from its input. The channels are selected by a variety of methods, which may be layered. The first method uses a text string to select channels by name or index. The second method uses a value range to select channels with samples within or outside the range. The third method selects constant-valued channels.

An option selects whether to delete or output the selected channels.

Parameters

Delete

Determines whether the selected channels should be deleted or retained.

Scoped Channels	The selected channels are deleted. The rest are output.
Non-Scoped Channels	The selected channels are output. The rest are deleted.

Select Channels

Chooses channel selection by name or by index.

Channel Names

The names of the channels to delete or extract. See the possible scope patterns below.

Channel Numbers

The indices of the channels to delete or extract. See possible number patterns below.

Channel Value

Chooses the type of value range selection:

Off	Do not perform range selection.
Channel Completely Within Range	All the channel’s samples must be within the specified range for it to be selected.
Channel Partially Within Range	At least one of the channel’s samples must be in the range for it to be selected.
Channel Completely Outside Range	None of the channel’s samples can be in the range for it to be selected.

Value Range

The lower and upper values of the range used for Range Selection.

Select Constant Valued Channels

Select channels which have the same value for all samples.

Common

Some of these parameters may not be avaiable on all CHOP nodes.

Scope

To determine which channels get affected, some CHOPs have a scope string. Patterns can be used in the 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.
`r[xyz]`	Matches channels `rx`, `ry` and `rz`.
`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 rate of first input to resample others.
Resample At Maximum Rate	Resample to 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 for which time parameters are specified.

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, it does not convert the existing parameters to the new units.

Time Slice

Time Slicing is a feature which boosts cooking performance and reduces memory usage. Traditionally, CHOPs calculate the channel over its entire frame range. If the channel does need 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 known as a 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 for display in the Graph port, but you can override the color in the Common page under 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.

Example files

Delete01

$HFS/houdini/help/examples/nodes/chop/delete/Delete01.cmd

Load | Launch

This example demonstrates how the Delete CHOP can remove or extract input channels by index number and pattern.

Delete02

$HFS/houdini/help/examples/nodes/chop/delete/Delete02.cmd

Load | Launch

This example demonstrates how the Delete CHOP can remove or extract input channels by selecting channel names.

Usages in other examples

Example name	Example for
ExtractTransforms	Dynamics channel node	Load \| Launch
Lookup	Lookup channel node	Load \| Launch