Inverse Kin CHOP
The Inverse Kin CHOP calculates an inverse kinematics simulation for Bone objects.
Parameters - Kinematics Page
solvertype - ⊞ - This parameter defines the method used to determine the motion of the Bone object when it, its ancestor, or its children are moved.
none- No motion solution is applied to the Bone object.
- Show Rest Position
rest- This solver is used to show the rest position of the bones. It orients the bones at the rest position defined by the rest angles in the chain. These rest angles are used in the Inverse Kinematics solver. Therefore, this solver can be used as a helper utility to show you the rest positions of the chain.
- Show Capture Position
capture- This solver is used to display the rotation values in the capture angles parameter. These parameters are set in the Skeleton sop when a "capture points" operation is performed, or by using the Grab Capture Angles menu. Like the Show Rest Position solver, this solver can be used to return a chain to its capture orientation.
- Inverse Kinematics
inverse- The IK solver tries to position the bones such that the end of the last bone in the chain touches the origin of the object defined as the end affector. The shape of the chain is derived from the rest angles of each the bones in the chain.
In order to adjust the results of the IK solver, you can adjust the rest angles of the bones. Note that the IK solver's solutions are guaranteed to be continuous only for a given set of rest angles. If you animate the rest angles you may end up with chains that jump around. When using kinematics, the rotations given by the kinematic solver can be exported to the bones using by enabling the export flag on the Inverse Kin CHOP. Adding rotation values to bone objects in a kinematic chain is not recommended, as those values will be over-written by the kinematic solver.
- IK with Constraints
- Follow Curve
curve- This solver positions the bones to be aligned along the first curve in an object. It is useful for animating things such as tails and spines.
boneroot - The starting bone of the chain; where the chain starts.
boneend - If you specify a bone as the last bone in chain, then you will be defining a bone chain that has the current bone as the first in the chain and the bone chosen from the menu as the final bone in the chain. This chain includes all bones in between those just chosen.
endaffector - This specifies which object will serve as the chain's end affector.
twistaffector - If you specify a twist affector, the entire bone chain will twist along the axis from the chain's root to its end-affector so that the first bone is pointing as much as it can at the twist affector. The twist value can be specified as well, and is applied on top of the twist generated for the twist affector.
iktwist - Amount of twist allowed by the kinematics solution.
ikdampen - Amount of damping (slows down at the extremes of angular allowability).
curve - Curve object to follow.
Parameters - Common Page
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 - 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.
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
autoexportroot - This path points to the root node where all of the paths that exporting by Channel Name is Path:Parameter are relative to.
exporttable - The DAT used to hold the export information when using the DAT Table Export Methods (See above).
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TouchDesigner is a hierarchy of components. "root" is the top-most network in the hierarchy. The Path is simply
/. A typical path is
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.
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'.