Expression CHOP

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Summary
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The Expression CHOP allows you to modify input channels by using math expressions. Up to six expressions are available. Each input channel is modified by exactly one expression, and the expressions are looped for multiple channels.

The output is the same length and set of channels as the first input, but its sample values are changed according to the expressions.

An expression is applied to each keyframe value or raw sample. There are up to six expressions. If there are more channels coming from input 0, the expressions are recycled. A repeat parameter controls how many channels to apply the first expression to before going on to the second expression.

The corresponding input values are me.inputVal in the expressions. me.inputs[1][0] gets from the first channel of the second input.

See also Evaluate DAT for easy evaluation of any expression.

PythonIcon.pngexpressionCHOP_Class


Parameters - Group Page

Channels per Expr chanperexpr - The number of channels that use the current expression before the next expression is selected.

Num Expressions numexpr - The total number of expressions that are defined.

Limit Output Channels limitexpr -

Number of Channels limitnum -


Parameters - Expr Page

Enter your expressions here. The input values are me.inputVal in the expressions. me.inputs[1]['chan1'] gets from the channel chan1 of the second input.

Expression 1 expr0 -  

Expression 2 expr1 -  

Expression 3 expr2 -  

Expression 4 expr3 -  

Expression 5 expr4 -  

Expression 6 expr5 -  


Parameters - Common Page

Time Slice timeslice - Turning this on forces the channels to be "Time Sliced". A Time Slice is the time between the last cook frame and the current cook frame.

Scope scope - To determine which channels get affected, some CHOPs use a Scope string on the Common page.

Sample Rate Match srselect - - Handle cases where multiple input CHOPs' sample rates are different. When Resampling occurs, the curves are interpolated according to the Interpolation Method Option, or "Linear" if the Interpolate Options are not available.

  • Resample At First Input's Rate first - Use rate of first input to resample others.
  • Resample At Maximum Rate max - Resample to the highest sample rate.
  • Resample At Minimum Rate min - Resample to the lowest sample rate.
  • Error If Rates Differ err - Doesn't accept conflicting sample rates.

Export Method exportmethod - - This will determine how to connect the CHOP channel to the parameter. Refer to the Export article for more information.

  • DAT Table by Index datindex - Uses the docked DAT table and references the channel via the index of the channel in the CHOP.
  • DAT Table by Name datname - Uses the docked DAT table and references the channel via the name of the channel in the CHOP.
  • Channel Name is Path:Parameter autoname - The channel is the full destination of where to export to, such has geo1/transform1:tx.

Export Root autoexportroot - This path points to the root node where all of the paths that exporting by Channel Name is Path:Parameter are relative to.

Export Table exporttable - The DAT used to hold the export information when using the DAT Table Export Methods (See above).


CHOPs
Ableton Link • Analyze • Angle • Attribute • Audio Band EQ • Audio Device In • Audio Device Out • Audio Dynamics • Audio File In • Audio Filter • Audio Movie • Audio Oscillator • Audio Para EQ • Audio Play • Audio Render • Audio Spectrum • Audio Stream In • Audio Stream Out • Beat • BlackTrax • Blend • Clip Blender • Clip • Clock • Composite • Constant • Copy • Count • CPlusPlus • Cross • Cycle • DAT to • Delay • Delete • DMX In • DMX Out • Envelope • EtherDream • Event • Expression • Extend • Fan • Feedback • File In • File Out • Filter • Function • Gesture • Handle • Helios DAC • Hog • Hokuyo • Hold • In • Info • Interpolate • Introduction To CHOPs id• Inverse Curve • Inverse Kin • Join • Joystick • Keyboard In • Keyframe • Kinect • Lag • Leap Motion • Leuze ROD4 • LFO • Limit • Logic • Lookup • LTC In • LTC Out • Math • Merge • MIDI In • MIDI In Map • MIDI Out • Mouse In • Mouse Out • NatNet In • Noise • Null • Object • Oculus Audio • Oculus Rift • OpenVR • OSC In • OSC Out • Out • Override • Panel • Parameter • Pattern • Perform • Pipe In • Pipe Out • PosiStageNet • Pulse • RealSense • Record • Rename • Render Pick • Reorder • Replace • Resample • S Curve • Scan • Script • Select • Sequencer • Serial • Shared Mem In • Shared Mem Out • Shift • Shuffle • Slope • SOP to • Sort • Speed • Splice • Spring • Stretch • Switch • Sync In • Sync Out • Tablet • Time Slice • Timeline • Timer • TOP to • Touch In • Touch Out • Trail • Transform • Trigger • Trim • Warp • Wave • ZED

A text string that contains data (string, float, list, boolean, etc.) and operators (+ * < etc) that are evaluated by the node's language (python or Tscript) and returns a string, float list or boolean, etc. Expressions are used in parameters, and in scripts.

An which operate on (a series of numbers) which are used for animation, audio, mathematics, simulation, logic, UI construction, and many other applications.

A Time Slice is the time from the last cook frame to the current cook frame. In CHOPs it is the set of short channels that only contain the CHOP channels' samples between the last and the current cook frame.

A parameter in most CHOPs that restricts which channels of that CHOP will be affected. Normally all channels of a CHOP are affected by the operator.

samples-per-second of a CHOP. Each CHOP in your network has a sample rate, whether it is used or not. The overall timeline has a "frame rate", which is the number of animation frames per second, generally your monitor display frequency.

Exporting is the connection of CHOP channels to parameters of operators. The output of each exporting CHOP is one or more channels, active only while the is on. The current value of a channel can be exported to a parameter of any operator, overriding that parameter's value. See .

An that manipulates text strings: multi-line text or tables. Multi-line text is often a command , but can be any multi-line text. are rows and columns of cells, each containing a text string.

The location of an operator within the TouchDesigner environment, for example, /geo1/torus1, a node called torus1 in a component called geo1. The path / is called . To refer instead to a filesystem folder, directory, disk file or http: address, see .

Parameters in TouchDesigner are an operator's settings (numbers, menus, flags, strings, paths) which the user can alter. Parameters for any operator can be opened by right-clicking on the operator and selecting "Parameters..." A currently selected operator's parameters can be viewed in a by pressing the keyboard shortcut 'p'.

TouchDesigner is a hierarchy of components. "root" is the top-most network in the hierarchy. The is simply /. A typical path is /project1/moviein1.