Keyboard channel node

Turns key presses into channel output.

See also: Audio In, MIDI In, Pipe In, Mouse

This CHOP listens for keyboard input (on up to nine keys), and outputs channel data. It creates a single-frame channel for the current state of each key.

Enter a channel name in a Name field, and choose a key using the corresponding Key menu.

Each key event gets routed to one destination in this order:

Input field (only if selected).
CHOPs (only if used).
Anywhere else.

Intercept Mode

The Keyboard CHOP can only be used while in “Intercept” mode. To enable Intercept mode, you need to have Scroll Lock on. To use the keypad number keys you must have Num Lock on.

When in Intercept mode, the Houdini Playbar will change to an orange color and all keyboard input will be redirected to any Keyboard chops. This means you cannot access any regular keyboard short-cuts (such as View state keyboard short-cuts, edit OP parameters, or use the Textport) while Intercept is on.

You can connect the Mouse and Keyboard CHOPs to the Position and Active inputs of the Record CHOP to record channels.

Parameters

Keyboard

Name

The name of the channel that monitors the selected key. If blank, a channel will not be created.

Type

How a key press affects the network.

Momentary	This is simply the up/down state of a key. 0 is up and 1 is down.
Toggle	This toggles the key state. Push once and it goes on (1), push again and it goes off (0).
Count	This increments the channel value by one every time the key is pressed. If the Alt key is also pressed, the channel value is decremented instead.
Pulse	This produces a one-frame pulse when a key is pressed.
Time	This returns the length of time that the key has been held down. It only works when the time bar is playing.

Key

The Key selector, where valid keys are the numbers 0-9, letters A-Z, and keypad 0-9.

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.

Usages in other examples

Example name	Example for