Bullet Solver COMP
In a Bullet Dynamics system, the Bullet Solver COMP is analogous to the world/simulation in which actors/bodies (ie. Actor COMPs) operate. A Bullet Solver COMP contains any number of actors/bodies (Actor COMPs) or forces (Force COMP/Impulse Force COMP), and as the name suggests it also uses the Bullet Physics API to step through the simulation.
The Bullet Solver COMP runs a Bullet simulation based on some simulation parameters (eg. linear multiplier or angular multiplier) and updates the transformations of the Actor COMPs contained within it as the simulation progresses forward. The simulation can be paused, slowed down, sped up, or restarted using the parameters on the COMP.
The Bullet Solver COMP simulation operates in a vacuum, so there will be no air resistance applied to any actors in the simulation. The simulation is stepped at the given sample rate, and the Actor COMP transform is updated accordingly. These transformations are the same results displayed in the Bullet Solver CHOP.
The Actor COMPs referenced by the Bullet Solver COMP do not need to be inside its network. They can be anywhere as long as they are not already referenced by another Bullet Solver COMP.
Parameters - Solver Page
actors - The Actor COMPs to include in the simulation. These actors cannot already be a part of another Bullet Solver COMP.
forces - The Force COMPs to include in the simulation. These forces are global forces and will be applied to all non-static actors in the simulation.
gravity - ⊞ - Gravity applied to all actors in the simulation in m/s^2. Gravity is applied to actors irrespective of their mass.
dimension - ⊞ - The dimension of the simulation. The options in this menu can also be recreated using the linear/angular multiplier parameters.
1d- Actor is constrained to linear velocity only on the X axis, with no angular velocity (linmult 1,0,0 and angmult 0,0,0)
2d- Actor is constrained to linear velocity only on the XY plane, with angular velocity only around the Z axis (linmult 1,1,0 and angmult 0,0,1)
3d- Actor is not constrained and can move in any direction: X, Y, or Z. Similarly, the Actor can also rotate in any direction: X, Y, or Z (linmult 1,1,1 and angmult 1,1,1)
linmult - ⊞ - A multiplier for the linear velocities of the actors in the simulation. For example, if linmult is (0, 1, 1) then the actors can move linearly at normal speed on the Y and Z axes but cannot move in the X direction. These values are multiplied internally by the values from dimension. For example, if the dimension is 2D and linmult is (0, 1, 1) then the only direction the actors can move is along the Y axis because 2D is constraining on the Z and this parameter is constraining on the Y.
angmult - ⊞ - A multiplier for the angular velocities of the actors in the simulation. For example, if angmult is (1, 0, 0) then the actors can only rotate on the X axes. These values are multiplied internally by the values from dimension. So, if dimension is 2D and angmult is (1, 0, 0) then the actor will not be able to rotate in any direction because 2D constrains rotation only to the Z axis, and this parameter is constraining it only to the X axis.
Initialize Sim and Collision Shapes
initall - Resets all bodies to their initial state (ie. position, orientation, velocity) and recreates their collision shapes. This parameter is equivalent to pulsing each Actor COMP's "Initialize Actor". Creating collision shapes can be time consuming in certain cases, so if it's not need then Initialize Sim should be used instead. Collision shapes need to be recreated if any of the SOPs used to create the collision shape change, or if the instancing OP changes.
init - Reset all bodies to their initial state (ie. position, orientation, velocity). This will not begin stepping through the simulation, it will only initialize. NOTE: This will not reset the collision shapes of any Actor COMPs, "Initialize Sim and Collision Shapes" above or "Initialize Actor" on the Actor COMP should be used for that.
start - Initialize the simulation and run it (begin stepping).
play - Play the simulation. Will step through the simulation when toggled on, but will not when it is toggled off (ie. it will be paused).
rate - The sample rate of the simulation. The sample rate affects the timestep, which is 1/rate
simspeed - The speed of the simulation. It is a multiplier for the size of the timestep to slow down or speed up the simulation.
feedback - (see also: Bullet Solver CHOP) A reference to a CHOP to feedback. The Bullet Solver COMP will take the transform/velocity channels from the CHOP and override the respective actor's transform or velocity at the beginning of the next simulation step.
If you feedback a Bullet Solver CHOP that has no change to the channel values in it, the simulation will act as normal as nothing is being overriden. This allows you do things like the example below.
For example, to negate the velocity of every actor in a simulation you could use a Bullet Solver CHOP, put that into a Switch CHOP with the second input being the same CHOP only with the velocity channels negated. Then export a button pulse to the switch index and put the Switch CHOP into the Feedback CHOP parameter. Then, when the button is pressed for a single frame (pulsed) the velocities will be overridden and negated.
The only channels required to feedback are the actor_id and body_id channels, all other channels are optional. The channel names should all be the same as in the Bullet Solver CHOP. In addition to the channels outputted in the Bullet Solver CHOP, force and torque can also be used. The channel names are force[xyz] and torque[xyz]. NOTE: scale cannot be used for feedback.
Perform Contact Test
contacttest - Enables contact testing for all bodies in the simulation. Contact testing is used for the colliding and total_collisions channels on the Bullet Solver CHOP. Without this parameter enabled those channel values will not update. NOTE: Contact testing can be slow for lots of bodies.
alwayssim - When enabled the Bullet Solver COMP will simulate (ie. cook) every frame.
callbacks - A reference to a DAT with python callbacks. The available callbacks are:
onStart(solverComp). A DAT with these callbacks will be automatically created and referenced when a Bullet Solver COMP is created.
onCollision(solverComp, collisions) passes a list of all collisions occuring, and requires that Perform Contact test be enabled.
collisions is a list of named tuples (
bodyB are the two bodies participating in the collision.
bodyB are Python Body Objects (see Body Class).
Parameters - Xform Page
The Xform parameter page controls the object component's transform in world space.
xord - ⊞ - The menu attached to this parameter allows you to specify the order in which the changes to your Component will take place. Changing the Transform order will change where things go much the same way as going a block and turning east gets you to a different place than turning east and then going a block. In matrix math terms, if we use the 'multiply vector on the right' (column vector) convention, a transform order of Scale, Rotate, Translate would be written as
T * R * S * Position.
- Scale Rotate Translate
- Scale Translate Rotate
- Rotate Scale Translate
- Rotate Translate Scale
- Translate Scale Rotate
- Translate Rotate Scale
rord - ⊞ - The rotational matrix presented when you click on this option allows you to set the transform order for the Component's rotations. As with transform order (above), changing the order in which the Component's rotations take place will alter the Component's final position. A Rotation order of Rx Ry Rz would create the final rotation matrix as follows
R = Rz * Ry * Rx
- Rx Ry Rz
R = Rz * Ry * Rx
- Rx Rz Ry
R = Ry * Rz * Rx
- Ry Rx Rz
R = Rz * Rx * Ry
- Ry Rz Rx
R = Rx * Rz * Ry
- Rz Rx Ry
R = Ry * Rx * Rz
- Rz Ry Rx
R = Rx * Ry * Rz
t - ⊞ - The three fields allow you to specify the amount of movement along any of the three axes; the amount, in degrees, of rotation around any of the three axes; and a non-uniform scaling along the three axes. As an alternative to entering the values directly into these fields, you can modify the values by manipulating the Component in the Viewport with the Select & Transform state.
r - ⊞ - The three fields allow you to specify the amount of movement along any of the three axes; the amount, in degrees, of rotation around any of the three axes; and a non-uniform scaling along the three axes. As an alternative to entering the values directly into these fields, you can modify the values by manipulating the Component in the Viewport with the Select & Transform state.
s - ⊞ - The three fields allow you to specify the amount of movement along any of the three axes; the amount, in degrees, of rotation around any of the three axes; and a non-uniform scaling along the three axes. As an alternative to entering the values directly into these fields, you can modify the values by manipulating the Component in the Viewport with the Select & Transform state.
p - ⊞ - The Pivot point edit fields allow you to define the point about which a Component scales and rotates. Altering the pivot point of a Component produces different results depending on the transformation performed on the Component.
For example, during a scaling operation, if the pivot point of an Component is located at
-1, -1, 0 and you wanted to scale the Component by
0.5 (reduce its size by 50%), the Component would scale toward the pivot point and appear to slide down and to the left.
In the example above, rotations performed on an Component with different pivot points produce very different results.
scale - This field allows you to change the size of an Component uniformly along the three axes.
Note: Scaling a camera's channels is not generally recommended. However, should you decide to do so, the rendered output will match the Viewport as closely as possible when scales are involved.
constrain - Allows the location of the object to be constrained to any other object whose path is specified in this parameter.
lookat - Allows you to orient your Component by naming the Component you would like it to Look At, or point to. Once you have designated this Component to look at, it will continue to face that Component, even if you move it. This is useful if, for instance, you want a camera to follow another Component's movements. The Look At parameter points the Component in question at the other Component's origin.
Tip: To designate a center of interest for the camera that doesn't appear in your scene, create a Null Component and disable its display flag. Then Parent the Camera to the newly created Null Component, and tell the camera to look at this Component using the Look At parameter. You can direct the attention of the camera by moving the Null Component with the Select state. If you want to see both the camera and the Null Component, enable the Null Component's display flag, and use the Select state in an additional Viewport by clicking one of the icons in the top-right corner of the TouchDesigner window.
Look At Up Vector
lookup - ⊞ - When specifying a Look At, it is possible to specify an up vector for the lookat. Without using an up vector, it is possible to get poor animation when the lookat Component passes through the Y axis of the target Component.
- Don't Use Up Vector - Use this option if the look at Component does not pass through the Y axis of the target Component.
- Use Up Vector - This precisely defines the rotates on the Component doing the looking. The Up Vector specified should not be parallel to the look at direction. See Up Vector below.
- Use Quaternions - Quaternions are a mathematical representation of a 3D rotation. This method finds the most efficient means of moving from one point to another on a sphere.
- Don't use up vector
- Use up vector
- Use quaternions
pathsop - Names the SOP that functions as the path you want this Component to move along. For instance, you can name an SOP that provides a spline path for the camera to follow.
Production Tip: For Smooth Motion Along a Path - Having a Component follow an animation path is simple. However, when using a NURBS curve as your path, you might notice that the Component speeds up and slows down unexpectedly as it travels along the path. This is usually because the CVs are spaced unevenly. In such a case, use the Resample SOP to redistribute the CVs so that they are evenly spaced along the curve. A caution however - using a Resample SOP can be slow if you have an animating path curve.
An alternative method is to append a Basis SOP to the path curve and change it to a
Uniform Curve. This way, your Component will move uniformly down the curve, and there is no need for the Resample SOP and the unnecessary points it generates.
roll - Using the angle control you can specify a Component's rotation as it animates along the path.
pos - This parameter lets you specify the Position of the Component along the path. The values you can enter for this parameter range from
0 equals the starting point and
1 equals the end point of the path. The value slider allows for values as high as
10 for multiple "passes" along the path.
Orient along Path
pathorient - If this option is selected, the Component will be oriented along the path. The positive Z axis of the Component will be pointing down the path.
Orient Up Vector
up - ⊞ - When orienting a Component, the Up Vector is used to determine where the positive Y axis points.
bank - The Auto-Bank Factor rolls the Component based on the curvature of the path at its current position. To turn off auto-banking, set the bank scale to
Parameters - Pre-Xform Page
The Pre-Xform parameter page applies a transform to the object component the same way connecting another Object as a parent of this node does. The transform is applied to the left of the Xform page's parameters. In terms of matrix math, if we use the 'multiply on the right' (column vector) convention, the equation would be
preXForm * xform * Position.
pxform - Enables the transformation on this page.
pxord - ⊞ - Refer to the documentation on Xform page for more information.
- Scale Rotate Translate
- Scale Translate Rotate
- Rotate Scale Translate
- Rotate Translate Scale
- Translate Scale Rotate
- Translate Rotate Scale
prord - ⊞ - Refer to the documentation on Xform page for more information.
- Rx Ry Rz
- Rx Rz Ry
- Ry Rx Rz
- Ry Rz Rx
- Rz Rx Ry
- Rz Ry Rx
pt - ⊞ - Refer to the documentation on Xform page for more information.
pr - ⊞ - Refer to the documentation on Xform page for more information.
ps - ⊞ - Refer to the documentation on Xform page for more information.
pp - ⊞ - Refer to the documentation on Xform page for more information.
pscale - Refer to the documentation on Xform page for more information.
preset - This button will reset this page's transform so it has no translate/rotate/scale.
Commit to Main Transform
pcommit - This button will copy the transform from this page to the main Xform page, and reset this page's transform.
xformmatrixop - This parameter can be used to transform using a 4x4 matrix directly. For information on ways to specify a matrix directly, refer to the Matrix Parameters page. This transform will be applied after the regular Pre-Transform transformation. That is, it'll be applied in the oder XformMatrix * PreXForm * Position.
Parameters - Render Page
material - Selects a MAT to apply to the geometry inside.
drawpriority - Determines the order in which the Components are drawn. Smaller values get drawn after (on top of) larger values.
pickpriority - When using a Render Pick CHOP or a Render Pick DAT, there is an option to have a 'Search Area'. If multiple objects are found within the search area, the pick priority can be used to select one object over another. A higher value will get picked over a lower value. This does not affect draw order, or objects that are drawn over each other on the same pixel. Only one will be visible for a pick per pixel.
wcolor - ⊞ - Use the R, G, and B fields to set the Component's color when displayed in wireframe shading mode.
lightmask - By default all lights used in the Render TOP will affect geometry renderer. This parameter can be used to specify a sub-set of lights to be used for this particular geometry. The lights must be listed in the Render TOP as well as this parameter to be used.
Parameters - Extensions Page
The Extensions parameter page sets the component's python extensions. Please see extensions for more information.
reinitextensions - Recompile all extension objects. Normally extension objects are compiled only when they are referenced and their definitions have changed.
Extension Object 1
extension1 - A number of class instances that can be attached to the component.
Extension Name 1
extname1 - Optional name to search by, instead of the instance class name.
Promote Extension 1
promoteextension1 - Controls whether or not the extensions are visible directly at the component level, or must be accessed through the
.ext member. Example:
Parameters - Common Page
parentshortcut - Specifies a name you can use anywhere inside the component as the path to that component. See Parent Shortcut.
opshortcut - Specifies a name you can use anywhere at all as the path to that component. See Global OP Shortcut.
Internal OP Shortcut 1
iopshortcut1 - Specifies a name you can use anywhere inside the component as a path to "Internal OP" below. See Internal Operators.
iop1 - The path to the Internal OP inside this component. See Internal Operators.
nodeview - ⊞ - Determines what is displayed in the node viewer, also known as the Node Viewer. Some options will not be available depending on the Component type (Object Component, Panel Component, Misc.)
- Default Viewer
default- Displays the default viewer for the component type, a 3D Viewer for Object COMPS and a Control Panel Viewer for Panel COMPs.
- Operator Viewer
opviewer- Displays the node viewer from any operator specified in the Operator Viewer parameter below.
opviewer - Select which operator's node viewer to use when the Node View parameter above is set to Operator Viewer.
Keep in Memory
keepmemory - Used only for Panel Components this keeps the panel in memory to it doesn't reload every time it is displayed.
enablecloning - Control if the OP should be actively cloned.
Enable Cloning Pulse
enablecloningpulse - Instantaneously clone the contents.
clone - Path to a component used as the Master Clone.
Load on Demand
loadondemand - Loads the component into memory only when required. Good to use for components that are not always used in the project.
externaltox - Path to a
.tox file on disk which will source the component's contents upon start of a
.toe. This allows for components to contain networks that can be updated independently. If the
.tox file can not be found, whatever the
.toe file was saved with will be loaded.
Reload .tox on Start
reloadtoxonstart - When on (default), the external .tox file will be loaded when the .toe starts and the contents of the COMP will match that of the external .tox. This can be turned off to avoid loading from the referenced external .tox on startup if desired (the contents of the COMP are instead loaded from the .toe file). Useful if you wish to have a COMP reference an external .tox but not always load from it unless you specifically push the Re-Init Network parameter button.
Reload Built-In Parameters
reloadbuiltin - When this checkbox is enabled, the values of the component's built-in parameters are reloaded when the .tox is reloaded.
Save Backup of External
savebackup - When this checkbox is enabled, a backup copy of the component specified by the External
.tox parameter is saved in the
.toe file. This backup copy will be used if the External
.tox can not be found. This may happen if the
.tox was renamed, deleted, or the
.toe file is running on another computer that is missing component media.
Sub-Component to Load
subcompname - When loading from an External
.tox file, this option allows you to reach into the
.tox and pull out a COMP and make that the top-level COMP, ignoring everything else in the file (except for the contents of that COMP). For example if a
.tox file named
geo1 as the Sub-Component to Load, will result in
geo1 being loaded in place of the current COMP. If this parameter is blank, it just loads the
.tox file normally using the top level COMP in the file.
reinitnet - This button will re-load from the external
.tox file (if present), followed by re-initializing itself from its master, if it's a clone.
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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.
An Operator Family that reads, creates and modifies 3D polygons, curves, NURBS surfaces, spheres, meatballs and other 3D surface data.
An Operator Family that associates a shader with a SOP or Geometry Object for rendering textured and lit objects.
Any component can be extended with its own Python classes which contain python functions and data.
A Parent Shortcut is a parameter on a component that contains a name that you can use anywhere inside the component to refer to that component using the syntax
parent.Name, for example
parent.Effect.width to obtain panel width.
There are four types of shortcuts: Application Shortcuts that are built-in to TouchDesigner's authoring interface, Panel Shortcuts that you create for any custom built panels, Parent Shortcuts for accessing a component from within that component, and Global OP Shortcuts that access a unique component from anywhere in TouchDesigner.
Any of the procedural data operators. OPs do all the work in TouchDesigner. They "cook" and output data to other OPs, which ultimately result in new images, data and audio being generated. See Node.
A custom interactive control panel built within TouchDesigner. Panels are created using Panel Components whose look is created entirely with TOPs.
To pulse a parameter is to send it a signal from a CHOP or python or a mouse click that causes a new action to occur immediately. A pulse via python is via the
.pulse() function on a pulse-type parameter, such as Reset in a Speed CHOP. A pulse from a CHOP is typically a 0 to 1 to 0 signal in a channel.
TOuch Environment file, the file type used by TouchDesigner to save your project.
Every component contains a network of operators that create and modify data. The operators are connected by wires that define where data is routed after the operator cooks its inputs and generates an output.