Transform CHOP

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The Transform CHOP takes translate, rotate, and/or scale channels and transforms them using the transform parameters in the CHOP. It can be used to:

  • Change the position and orientation of an object.
  • Convert a set of transform channels with a certain transform order into an equivalent set of channels with a different transform order.
  • Change the direction, starting point and scale of motion capture data.

At present, only one transform format exists: the transform defined by 12 channels (tx ty tz, rx ry rz, sx sy sz, px py pz) and a transform order.

The Transform CHOP expects the input channels to have names that end in the above names. Frequently the input channels come from an Object CHOP or Parameter CHOP. Examples are:

  • geo1:tx geo1:ty geo1:tz geo1:rx ...
  • headtx heaty headtz headrx
  • tx ty tz rx ... (what you would get from a Parameter CHOP)

The above defines a transformation matrix. This is multiplied by the transform matrix defined on the Transform page, and the CHOP outputs modified translate/rotate/etc. channels.

The channels of a Transform CHOP are frequently exported back to objects.

To affect only one set of channels coming into the CHOP, use the Scope parameter on the Common page with a pattern like geo1:


Parameters - Transform Page

This page defines the matrix used to transform the channels. The parameters used to create this matrix are Transform Order, Rotate Order, and the Translate, Rotate, Scale and Pivot parameters.

Transform Order xord - -

  • Scale Rotate Translate srt -
  • Scale Translate Rotate str -
  • Rotate Scale Translate rst -
  • Rotate Translate Scale rts -
  • Translate Scale Rotate tsr -
  • Translate Rotate Scale trs -

Rotate Order rord - -

  • Rx Ry Rz xyz -
  • Rx Rz Ry xzy -
  • Ry Rx Rz yxz -
  • Ry Rz Rx yzx -
  • Rz Rx Ry zxy -
  • Rz Ry Rx zyx -

Translate t - -

  • X tx -
  • Y ty -
  • Z tz -

Rotate r - -

  • X rx -
  • Y ry -
  • Z rz -

Scale s - -

  • X sx -
  • Y sy -
  • Z sz -

Pivot p - -

  • X px -
  • Y py -
  • Z pz -

Output Channels out - - Specify how the channels are output.

  • Translate/Scale/Rotate Channels trs - Output t[xyz], r[xyz], s[xyz] channels.
  • 4x4 Matrix mat - Output a 16 channels which are the 16 values of a 4x4 transformation matrix. The translate column is contained in the last 4 channels.

Matrix Operation matop - - The input channels can be pre or post transformed by the transformation parameters. The pre-transformation is the same as using Pre-XForm parameters on a Geometry COMP. In mathematical terms, if we assume a multiply "vector on the right" convention (column vectors), a pre-transformation would be PreXForm * InputXForm, and a regular transform would be the opposite.

  • Transform Input transform -
  • Pre-Transform Input pretransform -

Use Rotation Hint usehint - Turning this on and using the Hint parameter below allows you to specify approximate starting values for the rotation channels produced. This allows you to change the rotation channel solution to a specific starting point (e.g. for camera output control).  

Hint hint - - Specify approximate starting values for the rotation channels produced.

  • X hintx -
  • Y hinty -
  • Z hintz -

Parameters - Input Page

This page defines what the incoming channels' transform order is assumed to be. Using the incoming channels and the transform order here, a matrix for the incoming channels in built. It is then multiplied by the transformation matrix defined by the Transform page and output.

Any missing translation, rotation or scale channels will default to zero (or one in the case of scale).

Transform Order inxord - - The transform order of the input channels. If the channels are retrieved from an object, this should be set to the same transform order as the object.

  • Scale Rotate Translate srt -
  • Scale Translate Rotate str -
  • Rotate Scale Translate rst -
  • Rotate Translate Scale rts -
  • Translate Scale Rotate tsr -
  • Translate Rotate Scale trs -

Rotate Order inrord - - The rotation order of the input rotations.

Note: When creating rotation channels, the Transform and Object CHOPs will select values which minimize frame-to-frame discontinuities. The graphs will appear continuous and free of 180 degree shifts. The Transform CHOP can be used to smooth out rotation channels derived from outside sources, such as the origin() function.

  • Rx Ry Rz xyz -
  • Rx Rz Ry xzy -
  • Ry Rx Rz yxz -
  • Ry Rz Rx yzx -
  • Rz Rx Ry zxy -
  • Rz Ry Rx zyx -

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).  

Operator Inputs

  • Input 0 -

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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.

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.

The component types that are used to render 3D scenes: Geometry Component contain the 3D shapes to render, plus Camera, Light, Ambient Light, Null, Bone, Handle and other component types.

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.

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.