Null CHOP

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Summary
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The Null CHOP is used as a place-holder and does not alter the data coming in.

It is often used to Export channels to parameters, which allows you to experiment with the CHOPs that feed into the Null without having to un-export from one CHOP and re-export from another.

The Null CHOP also has options to force-cook nodes downstream from it, or the opposite, to stop cooking nodes downstream if its inputs are not changing.

NullCHOP.jpg

PythonIcon.pngnullCHOP_Class


Parameters - Null Page

Cook Type cooktype - - This controls how nodes downstream from the Null CHOP are triggered for recooking when the Null CHOP output changes. See also: Cook

  • Automatic auto - Downstream nodes are triggered for recooking normally.
  • Always always - This node and dirty upstream nodes will cook every frame. Downstream nodes will recook every frame their data is requested.
  • Selective selective - Select which criteria will cause downstream nodes to require recooking, using the parameters below. This option can optimize your network by reducing the number of cooks downstream if the upstream CHOP has inputs that are time dependent or changes often, but output is mostly static (e.g. a Math CHOP rounding a constantly changing float to 0 or 1). The downside is that the nodes upstream of the Null will cook whenever something changes, even if no data is requested downstream. See Cook for more information on when data is requested.

Check Values checkvalues - Recook when the Null CHOP values change.

Check Names checknames - Recook when the Null CHOP channel names change.

Check Range checkrange - Recook when the Null CHOP channel range changes.

Please note that downstream cooks may also cook for a variety of reasons including viewing the contents of the data while editing nodes, etc.


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 • Experimental:Audio NDI • Audio Oscillator • Audio Para EQ • Audio Play • Audio Render • Audio Spectrum • Audio Stream In • Audio Stream Out • Beat • BlackTrax • Blend • Experimental:Bullet Solver • 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 • Experimental:Import Select • 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

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

To re-compute the output data of the Operators. An operator cooks when (1) its inputs change, (2) its Parameters change, (3) when the timeline moves forward in some cases, or (4) Scripting commands are run on the node. When the operator is a Gadget, it also cooks when a user interacts with it. When an operator cooks, it usually causes operators connected to its output to re-cook. When TouchDesigner draws the screen, it re-cooks all the necessary operators in all Networks, contributing to a frame's total "cook time".

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 CHOP Viewer is on. The current value of a channel can be exported to a parameter of any operator, overriding that parameter's value. See Parameter.

An Operator Family that manipulates text strings: multi-line text or tables. Multi-line text is often a command Script, but can be any multi-line text. Tables 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 Root. To refer instead to a filesystem folder, directory, disk file or http: address, see Folder.

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 Network Editor by pressing the keyboard shortcut 'p'.

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