VEX Waveform channel node

This function is a sub-set of the waveform CHOP.

This function is a sub-set of the waveform CHOP.

Parameters

Waveform

Wave Type

The wave type which is one of the following:

Constant

A constant valued “wave”.

Sine

A sine wave.

Gaussian

A Gaussian wave (also known as bell or normal curve).

Triangle

A triangular sawtooth wave.

Square

A square wave.

Pulse

A periodic one-sample pulse wave.

Expression

A user defined non-periodic expression.

Period

The period of the wave.

Phase

The phase of the wave, from 0 to 1.

Bias

The bias of the waveform. Only Gaussian, triangle and square waves have biases.

Offset

The value offset of the waveform.

Amplitude

The amplitude of the waveform.

Decay

The decay rate of the waveform, represented as the fraction of decay after 1 Unit of time (default is one second)

Ramp Slope

A ramp is added the wave: amount per Unit of time.

Channel

Align

The alignment option to use.

Extend to Min/Max

Find the earliest start and latest end, and extend all inputs to that range using the extend conditions.

Stretch to Min/Max

Find the earliest start and latest end, and stretch every channel’s start and end to that range.

Shift to Minimum

Find the earliest start and shift all channels so they all start at that index. All channels are extended to the length of the longest one.

Shift to Maximum

Find the latest end and shift all channels so they all end at that index. Extend all channels to the length of the longest one.

Shift to First Interval

Shift all channels to the start of the first channel and sample all inputs using the first input’s range.

Trim to First Interval

Trim all channels to first channel’s range.

Stretch to First Interval

Stretch all channels to the first channel’s range.

Trim to Smallest Interval

Trim all channels to the smallest start/end interval. The start and end values may not come from the same channel.

Stretch to Smallest Interval

Stretch all channels to the smallest start/end interval. The start and end values may not come from the same channel.

Channel Name

The names of the channels to create. Patterns like chan[1-20] generate multiple channels.

Start, End

The start time of the channels.

Sample Rate

The sample rate of the channels.

Edit VEX Function

Opens the Edit Operator Type Properties dialog.

Re-load VEX Functions

Reloads VEX Functions.

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