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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.

PythonIcon.pngbulletsolverCHOP_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).   TouchDesigner Build: