Close

Privacy policy

Follow us

https://www.instagram.com/touchdesigner/
https://www.facebook.com/TouchDesigner
https://twitter.com/1null1
https://www.youtube.com/TouchDesignerOfficial
All
User Guide
Forum
Tutorials
Events & Workshops
Features
Community
Showcase
Resources
  1. Home
  2. Expression CHOP

    Expression CHOP

    Summary

    The Expression CHOP allows you to modify input channels by using math expressions. 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. If there are more channels coming from input 0 than expressions, the expressions are recycled. A Channels per Expression 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 - Expression Page

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

    Limit Output Channels limitexpr - Turn On this parameter to limit the number of channels the Expression CHOP will output.

    Number of Channels limitnum - When the above parameter is On, set the maximum number of channels to output.

    Expression expr - The sequence of expressions used

    Expression expr0expr - Enter your expression here. The input values are me.inputVal in the expressions. me.inputs[1]['chan1'] gets from the channel chan1 of the second input.


    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. See Pattern Matching.

    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).


    Operator Inputs

    • Input 0: -


    Info CHOP Channels

    Extra Information for the Expression CHOP can be accessed via an Info CHOP.

    Common CHOP Info Channels

    • start - Start of the CHOP interval in samples.
    • length - Number of samples in the CHOP.
    • sample_rate - The samplerate of the channels in frames per second.
    • num_channels - Number of channels in the CHOP.
    • time_slice - 1 if CHOP is Time Slice enabled, 0 otherwise.
    • export_sernum - A count of how often the export connections have been updated.

    Common Operator Info Channels

    • total_cooks - Number of times the operator has cooked since the process started.
    • cook_time - Duration of the last cook in milliseconds.
    • cook_frame - Frame number when this operator was last cooked relative to the component timeline.
    • cook_abs_frame - Frame number when this operator was last cooked relative to the absolute time.
    • cook_start_time - Time in milliseconds at which the operator started cooking in the frame it was cooked.
    • cook_end_time - Time in milliseconds at which the operator finished cooking in the frame it was cooked.
    • cooked_this_frame - 1 if operator was cooked this frame.
    • warnings - Number of warnings in this operator if any.
    • errors - Number of errors in this operator if any.


    TouchDesigner Build: