Bullet Solver CHOP

Summary

The Bullet Solver CHOP is used in conjunction with a Bullet Dynamics system. It outputs the solved results from a Bullet simulation and can include the results for the entire system (Bullet Solver COMP) or an individual actor (Actor COMP) within a system.

The Bullet Solver CHOP can also be used with the "Feedback CHOP" parameter on the Bullet Solver COMP or Actor COMP. Bullet Solver simulation results can be grabbed using the Bullet Solver CHOP, modified, then fed back into the Bullet Solver COMP it came from. The values at the beginning of the next step of the simulation will be whatever values are in the CHOP that is fed back. This allows any CHOP data to be injected into the simulation at the beginning of the next frame (time step).

For example: making an actor in the simulation jump to the mouse cursor when clicked.

Output Channels:

• actor_id: the OP id of the Actor COMP
• body_id: the id of the body within the Actor COMP. Actor COMPs can have multiple bodies if they are static or if instancing (see: Actor COMP). Body id's increment from 0 to N-1, where N is the total number of bodies in an Actor COMP.
• active: whether the body is active in the simulation
• colliding: whether the body is currently colliding with another body
• colliding_actor_id the ID of the Actor COMP that contains the body we are colliding with
• colliding_body_id the ID of the body we are colliding with; together with colliding_actor_id will map back to a specific body in the simulation
• total_collisions: the total number of collisions this body has had
• t[xyz]: the translation of the body in the given transform space
• r[xyz]: the rotation of the body in the given transform space
• s[xyz]: the scale of the body in the given transform space
• vel_t[xyz]: linear velocity of the body
• vel_r[xyz]: angular velocity of the body

See also: Bullet Dynamics, Bullet Solver COMP, Actor COMP, Force COMP, Impulse Force COMP, Constraint COMP.

bulletsolverCHOP_Class

Parameters - General Page

Solver or Actor COMP comp - A reference to either a Bullet Solver COMP or Actor COMP. If a Bullet Solver COMP is referenced then the CHOP will output the simulation results for all of its actors. If an Actor COMP is referenced then the CHOP will output the simulation results for only that actor.

Transform Space xformspace - ⊞ - The space in which to output the transformation values. That is, the transform values (translation/rotation) will be outputted relative to the selected space.

• World world - The output transform is in the world coordinate system.

• Bullet Solver bulletsolver - The transform output is relative to the Bullet Solver COMP.

• Actor actor - The output transform is relative to the Actor COMP.

Collision Info collisioninfo - Adds colliding, colliding_actor_id, colliding_body_id, and total_collisions channels to the CHOP. In order to track these values for a body, "Perform Contact Test" must be enabled on the Bullet Solver COMP.

Translation trans - Adds translation channels to the CHOP.

Rotation rot - Adds rotation channels to the CHOP.

Scale scale - Adds scale channels to the CHOP.

Linear Velocity linvel - Adds linear velocity channels to the CHOP.

Angular Velocity angvel - Adds angular velocity channels to the CHOP.

Sample Rate rate - The sample rate of the CHOP.

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).

Info CHOP Channels

Extra Information for the Bullet Solver 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: Latest\n2021.100002019.146502018.28070before 2018.28070

An Operator Family which operate on Channels (a sequence of numbers (Samples)) which are used for animation, audio, mathematics, simulation, logic, UI construction, and data streamed from/to devices and protocols.

An Operator Family that contains its own Network. There are sixteen 3D Object Component and ten 2D Panel Component types. See also Network Path.

samples-per-second of a CHOP. Each CHOP in your network has a sample rate. In contrast, the overall timeline has a Frame Rate, which is the number of frames to cook and display per second, generally your monitor display frequency, default 60.

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 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. TOPs have Channel Mask, a similar feature.

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 python Script or GLSL Shader, 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/circle1, a node called circle1 in a component called geo1. The path / is called Root. This path is displayed at the top of every Pane, showing which Component's network you are currently in. To refer instead to a filesystem folder, directory, disk file or http: address, see Folder.

Every operator in TouchDesigner has a set of Parameters that can be integer or floating point numbers, menus, binary toggles, strings, operator paths) which determine the output of the operator.

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