quattomatrix expression function

Converts quaternion to a 3×3 rotation matrix.

```quattomatrix(q) ```

Expression functions

• Returns the absolute value of the argument.

• Returns the full path of a file.

• Returns the arc-cosine of the argument.

• Returns the angular velocity required to rotate an object from one orientation to another in a certain period of time.

• Returns the arc length of a curve between two U positions.

• Returns the arc length of a curve between two U positions and number of divisions.

• Returns an argument from a list of HScript-style arguments.

• Returns the number of arguments in an HScript-style list of arguments.

• Returns the arc-sine of the argument.

• Returns the arc-tangent of the argument.

• Returns the arc-tangent of y/x.

• Converts a string to a float.

• Returns a space-separated list of attribute names.

• Returns bounding box information for a surface node.

• Channel segment function: Bezier interpoloation spline

• Combines two numbers with bitwise-and.

• Combines two numbers with bitwise-or.

• Sets or clears a bit in a number.

• Returns if a given bit is set.

• Combines two numbers with bitwise-xor.

• Returns the angle at the joint between two bone objects.

• Returns the smallest integer not less than the value passed in.

• Returns centroid information for a surface node.

• Returns the value of a parameter.

• Returns 1 if the specified channel exists, 0 if it doesn’t.

• Evaluates a channel with a new segment expression.

• Evaluates a channel with a new segment expression at a given frame.

• Evaluates a channel with a new segment expression at a given time.

• Evaluates a parameter at a given frame.

• return a string containing all of the channels contained in a group.

• Evaluates a channel within a CHOP at the current time.

• Evaluates a channel within a CHOP at a given time.

• Evaluates a channel within a CHOP at a specified sample point.

• Evaluates a channel within a CHOP at a specified time.

• Returns the end index of the channels in a CHOP.

• Evaluates a channel within a CHOP with at a given frame.

• Evaluates a channel within a CHOP at a given sample point.

• Returns the length of the channels in a CHOP, in samples.

• Returns the number of data channels within a CHOP.

• Returns the names of all the data channels within a CHOP.

• Returns the sample rate of a CHOP.

• Returns the start index of a CHOP.

• Returns the string value of a channel within a CHOP at the current time.

• Returns the value of a channel within a CHOP at a specified time.

• Returns the value of a ramp parameter at a specific position.

• Returns the value of a ramp parameter at a specific position and frame.

• Returns the value of a ramp parameter at a specific position and time.

• Evaluates the string value of a parameter at the current time.

• Evaluates the parameter at the current time as a node path string.

• Evaluates the parameter at the current time as a node path list string.

• Returns the raw (unexpanded) expression value of a parameter as a string.

• Returns the value of a parameter at a specified time.

• Returns a value clamped between a minimum and maximum.

• Clamps a vector to always end between a minimum and maximum sphere.

• Channel segment function: constant value.

• Returns the value of context option as a floating point value.

• Returns a cook context option as a string value.

• Tests if metadata exists on a compositing node.

• Tests if a plane exists on a compositing node.

• Returns numeric metadata from a compositing node.

• Returns string metadata from a compositing node.

• Returns the cosine of the argument.

• Returns the hyperbolic cosine of the argument.

• Computes the cross-product of two vectors.

• Channel segment function: cubic spline.

• Deprecated: current working container for custom panels.

• Deprecated: data type of a gadget, for custom panels.

• Deprecated: returns a value from a custom panel.

• Returns the curvature of the surface at the given UV coordinates.

• Deprecated: Returns the type of a gadget on a custom panel.

• Channel segment function: repeats animation from previous frames.

• Channel segment function: repeats the animation between frames f1 and f2, accumulating the value.

• Channel segment function: repeats the animation between times t1 and t2, accumulating the value.

• Channel segment function: repeats animation from previous frames.

• Decodes a variable name that was previously encoded.

• Decodes a geometry attribute name that was previously encoded.

• Decodes a node parameter name that was previously encoded.

• Converts from radians to degrees.

• Returns the degree a specified face or hull.

• Returns the value of a detail attribute.

• Returns a space-separated list of detail attribute names.

• Returns the number of components in a detail attribute.

• Returns the type of a detail attribute.

• Returns the string value of a detail attribute.

• Returns a string from a list of strings in a detail attribute.

• Returns the number of unique strings bound to a detail attribute.

• Returns components of a string array attribute.

• Returns the determinant of a matrix.

• Computes the dihedral matrix between vectors v0 and v1.

• Returns the distance between two 3D points.

• Returns a space separated list of all the field names that can be passed to the dopfield function.

• Returns the full path of the node connected to a dopnetwork.

• Returns the number of records of a given type in a piece of dynamics data.

• Returns the value of a field as a float.

• Returns the name of a DOP field.

• Returns the value of a DOP field as a string.

• Returns the type of a DOP field.

• Returns the current frame of the simulation.

• Returns the simulation time equivalent of a simulation frame.

• Returns 1 if a specified DOP group contains a specified object.

• Returns 1 if a specified DOP group is mutually affecting.

• returns a string containing a list of all object groups for the current time in a specified DOP Network.

• Returns 1 if a specified DOP field exists.

• Returns 1 if a dynamics object has the specified subdata.

• Returns the list of objects processed by a DOP in the latest timestep.

• Returns the number of fields in a DOP record type.

• returns the number of objects in a simulation.

• Returns the number of records of a given type in a piece of dynamics data.

• Returns the number of types of record in a piece of dynamics data.

• Returns the number of subdata items attached to an object or data.

• Returns all objects matching the an object specification.

• Tests whether a set of objects has an affector relationship with another object.

• Returns the list of objects created by a particular DOP node.

• Returns the value of a DOP field as a float.

• Returns the value of a DOP field as a string.

• Returns the name of a record in DOPs data given its index.

• Script solver support function.

• Script solver support function.

• Script solver support function.

• Script solver support function.

• Script solver support function.

• Script solver support function.

• returns the simulation frame of a given simulation time.

• Returns the global time of a given simulation time.

• Returns the name of a subdata of a given DOP object.

• Returns the current time of a simulation.

• Returns a transformation matrix associated with a piece of data.

• Returns the simulation time equivalent to a given global time.

• Returns the velocity that a point at a location in simulation space would have if it were attached to a DOP object.

• Computes the dot product of two vectors.

• Channel segment function: ease-in and -out.

• Channel segment function: ease-in.

• Channel segment function: ease-in with configurable acceleration.

• Channel segment function: ease-out

• Channel segment function: ease-out with configurable acceleration.

• Channel segment function: ease-in and -out with configurable acceleration.

• Returns the list of edge groups in a surface node.

• Returns the list of edge groups matching a pattern in a surface node.

• Fits a value from one range to another.

• Encodes any string into a valid variable name.

• Encodes any string into a valid geometry attribute name.

• Encodes any string into a valid node parameter name.

• Evaulates a string as an expression returning a float.

• Evaulates a string as an expression returning a string.

• Runs a string as an HScript command and returns the command’s output.

• Runs a string as an HScript command and returns the command and error output.

• Runs a string as an HScript command and returns any error output.

• Returns the logarithmic exponentiation of the argument.

• Explodes a 3×3 or 4×4 matrix into the euler rotations required to rebuild it.

• Explodes a 3×3 or 4×4 matrix into the euler rotations required to rebuild it.

• Explodes a 3×3 or 4×4 matrix into the euler rotations required to rebuild it.

• Searches the Houdini path for a file.

• Searches the Houdini path for a file or directory.

• Fits a value from one range to another.

• Fits a value to the 0-1 range.

• Fits a number in the 0-1 range.

• Fits a number to the -1 to 1 range.

• Returns the largest integer not greater than a number.

• Returns a string padding a number to a given length with zeros.

• Returns the fractional part of a floating-point number.

• Converts a number to a string.

• Converts a number to a string, with rounding.

• Returns a string describing the set of elements with a given value for an integer attribute.

• Returns a string describing the set of elements with a given value for a string attribute.

• Returns a non-zero value if the specified context option exists.

• Returns 1 if a specified detail attribute exists.

• Returns 1 if the active PDG work item has the specified attribute.

• Returns 1 if a specified point is in a specified group.

• Returns 1 if a specified point attribute exists.

• Returns 1 if a specified primitive is in a specified group.

• Returns 1 if a specified primitive attribute exists.

• Returns 1 if a specified vertex attribute exists.

• Converts a hexadecimal argument string into an integer.

• Converts RGB values to HSV components.

• Evaluates a CHOP’s input channel at a specific index.

• Returns the end index of a CHOP’s input.

• Returns the length of a CHOP’s input, in samples.

• Evaluates a CHOP’s input channel’s maximum value.

• Evaluates a CHOP’s input channel’s minimum value.

• Returns the number of channels in a CHOP’s input.

• Returns the sample rate of a CHOP’s input.

• Returns the start index of a CHOP’s input.

• Creates an identity matrix.

• Returns the value of the second or third argument depending on the truth of the first argument.

• Returns the string value of the second or third argument depending on the truth of the first argument.

• Finds the first occurrence of a pattern in a string.

• Returns the point number currently being instanced onto.

• Converts a number to an integer by truncating any fractional part.

• Converts a number into a hexadecimal string.

• Inverts a matrix.

• Queries numeric (floating point) data from an interactive render pane.

• Queries textual (string) data from an interactive render pane.

• Returns 1 if a primitive is closed.

• Returns 1 if a specified point has collided with something.

• Returns 1 if a specified Houdini environment variable exists.

• Returns 1 if the parameter is being evaluated as part of a PDG cook, else 0

• Returns 1 if a specified primitive is a NURBs or Bezier curve or surface.

• Returns 1 if a specified point is a stuck particle.

• Returns 1 if a specified Houdini or system environment variable exists.

• Returns 1 if a specified primitive is wrapped in U.

• Returns 1 if a specified primitive is wrapped in V.

• Returns the length of a vector.

• Channel segment function: linear interpolation.

• Returns a list of elements with a given value for an integer attribute.

• Returns a list of elements with a given value for a string attribute.

• Returns a value that cannot be changed.

• Returns the natural logarithm of the argument.

• Returns the base 10 logarithm of the argument.

• Returns the path of the USD primitive last modified by an input to a LOP node.

• Returns the paths of the USD primitives last modified by an input to a LOP node.

• Returns the path of the USD primitive last modified by a LOP node.

• Returns the paths of the USD primitives last modified by a LOP node.

• Returns the paths of the parents of the supplied list of USD primitives.

• Returns the paths at a particular location relative to the supplied list of USD primitives.

• Channel segment function: matches the incoming and outgoing values.

• Channel segment function: matches the incoming slope.

• Channel segment function: matches the outgoing slope.

• Converts a string specification into a matrix.

• Converts a rotation matrix to a quaternion.

• Returns the larger of two values.

• Returns the number of columns in a matrix.

• Returns the weight of a metaball at a specific location.

• Returns the smaller of two values.

• Finds the smallest distance between a point and a primitive.

• Computes the transformation matrix of a lookat from one vector to another.

• Computes the transformation matrix of a lookat from one vector to another, with an up vector.

• Computes the transformation matrix of a lookat from one object to another.

• Blends the two modular values.

• Computes the transformation matrix to orient along specific Z and Y axes.

• Returns the full name of the pane currently under the mouse pointer.

• Returns the node path of the pane currently under the mouse pointer.

• Returns the number of rows in a matrix.

• Returns a matrix with all values set to 0.

• Finds the point in a geometry nearest to specific 3D coordinates.

• Generates 3D noise.

• Returns the components of the surface normal specific UV coordinates.

• Normalizes a vector.

• Returns the number of points in a geometry.

• Returns the number of points in the specified group.

• Returns the number of primitives in a surface node.

• Returns the number of primitives in the specified group.

• Returns the number of unique values for an integer or string attribute in a surface node.

• Returns the number of vertices in a geometry.

• Returns the number of vertices in the specified group.

• Returns the current global kinematic override setting for bone objects.

• Returns a list of lights matching an object’s light mask.

• Computes the rotation vector of a lookat from one object to another.

• Returns an object’s pre-transform matrix.

• Returns the value of a CHOP’s output at a specific sample index.

• Queries the current OpenCL device with the provided flag

• Returns a pseudo-random number between 0 and 1.

• Returns the full paths of all operators in a bundle.

• Returns the creator of this node.

• Returns the numeric suffix of a node name.

• Returns 1 if the specified node, group, or bundle exists.

• Returns a list nodes with a particular flag set.

• Returns the full path of a node.

• Returns the path of a node relative to another node.

• Returns the unique ID of a node.

• Returns the name of the node connected to a given input.

• Returns the full path of the node connected to a given input.

• Returns the value associated with a key string on node connection.

• Returns 1 if Houdini is currently shutting down.

• Returns a list of lights matching an object’s light mask.

• Sorts a list of node paths based on node input/outputs order.

• Returns the name of a node given its path.

• Returns the number of nodes inside a container node.

• Returns the maximum number of connected inputs.

• Returns the alphanumeric prefix of a node name eliminating trailing digits.

• Returns the number of nodes connected to a node’s output.

• Returns the name of a node connected a given node’s output.

• Returns the full path of a node connected a given node’s output.

• Deprecated: replaced by opinput.

• Returns the path of the current network.

• Prints the path of the current network.

• Returns the relative path from one node to another.

• Returns a list of the selected nodes.

• Returns a list of the full paths of selected nodes.

• Returns a recursive list of the selected nodes.

• Returns a recursive list of the full paths of selected nodes.

• Computes the active stream of a node.

• Returns the full path of a node including any containing subnets.

• Returns the transformation matrix of an object at the current time.

• Returns the type of a node.

• Returns type information about a node.

• Returns components of an object’s transforms.

• Returns components of an object’s offset transforms.

• Returns a string padding a number to a given length with zeros.

• Returns 1 if a specified parameter is a string.

• Returns the value of a PDG work item attrib

• Returns a space-separated list of attribute names on the active PDG work item.

• Returns the string value of a PDG work item attribute

• Returns the number of components in a PDG work item attribute.

• Returns the type of a PDG work item attribute.

• Deprecated: replaced by pdgattrib.

• Deprecated: replaced by pdgattribs.

• Returns the space separated list of values for a PDG work item attribute

• Returns a work item input file for the specified file index and tag

• Returns the number of input files on the active PDG work item

• Returns the file tag for the input file at the specified index.

• Returns a space separated string of all work item input files for the specified tag

• Maps the given path to the local Zone

• Returns a work item output file for the specified file index and tag

• Returns the number of output files on the active PDG work item

• Returns the file tag for the output file at the specified index.

• Returns a space separated string of all work item output files for the specified tag

• Returns the color of a pixel in a compositing node.

• Returns the non-interpolated color of a pixel in a compositing node.

• Converts an English noun to its plural.

• Returns the value of a point attribute.

• Returns a space-separated list of point attribute names.

• Returns the number of components in a point attribute.

• Returns the type of a point attribute.

• Returns the average of an attribute across all points in a geometry.

• Returns the distance between a point and a primitive.

• Returns the list of point groups in a surface node.

• Returns the list of point groups matching a pattern in a surface node.

• Returns a list of all points in a point group.

• Lists points that share a minimum number of primitives with a specified point.

• Returns a list of points that match a specified pattern.

• Returns the string value of a point attribute.

• Returns a string from a list of strings in a point attribute.

• Returns the number of unique strings bound to a point attribute.

• Returns components of a string array attribute.

• Raises a number to an exponent.

• Returns the value of a primitive attribute.

• Returns a space-separated list of primitive attribute names.

• Returns the number of components in a primitive attribute.

• Returns the type of a primitive attribute.

• Returns the minimum distance and closest points between two primitives.

• Returns the partial derivatives of a primitive attribute.

• Returns the list of primitive groups in a surface node.

• Returns the list of groups matching a pattern in a surface node.

• Returns a list of all primitives in a surface node.

• Lists primitives that share a minimum number of points with a specified primitive.

• Returns the string value of a primitive attribute.

• Returns a string from a list of strings in a primitive attribute.

• Returns the number of unique strings bound to a primitive attribute.

• Returns the value of a primitive attribute at a certain UV location.

• Returns components of a string array attribute.

• Prints a message to the console.

• Similar to ch(), but for render properties, with a default if the property doesn’t exist.

• Evaluates a render property at a given frame.

• Evaluates the string value of a render property at the current time.

• Evaluates a render property at the current time as a node path string.

• Evaluates the raw (unexpanded) string value of a render property at the current time.

• Evaluates a render property at a given time.

• Returns 1 when a value is within a certain range.

• Evaluates a Python expression, returning a float result.

• Evaluates a Python expression, returning a string result.

• Channel segment function: uses quaternions to interpolate.

• Converts quaternion to a 3×3 rotation matrix.

• Channel segment function: smoothly interpolates slopes and accelerations.

• Converts from degrees to radians.

• Returns a pseudo-random number from 0 to 1.

• Channel segment function.

• Converts unit UV to real UV.

• Returns the relative path of a file.

• Channel segment function: repeats animation from previous frames.

• Channel segment function: repeats animation from previous frames.

• Returns the natural resolution of the image in a compositing node.

• Converts HSV values to RGB components.

• Finds the last occurrence of a pattern in a string.

• Rounds to the nearest integer.

• Returns a 4×4 rotation matrix from an axis and angle.

• Returns a 4×4 rotation matrix from an angle and a vector.

• Rounds a number to the nearest integer.

• Runs a string as an HScript command and returns the command’s output.

• Runs a string as an HScript command and returns the command and error output.

• Runs a string as an HScript command and returns any error output.

• Takes three scaling values and returns a scale matrix.

• Returns the scale factor converting from MKS units to the Houdini units.

• Returns the scale factor converting to MKS units from the Houdini units.

• Lists all seam points in a surface node.

• Returns 1 if a specified compositing node has an animated sequence.

• Returns the end frame of a compositing node’s image sequence.

• Returns the number of frames in a compositing node’s image sequence.

• Returns the start frame of a compositing node’s image sequence.

• Returns -1, 0, or 1 depending on the sign of the argument.

• Returns the sine of the argument.

• Returns the hyperbolic sine of the argument.

• Takes a value and range and returns a smooth interpolation between 0 and 1.

• Generates sparse convolution 3D noise.

• Returns a knot value on a spline curve or surface.

• Channel segment function: fits a curve to the keyframes.

• Returns the square root of the argument.

• Returns a copy stamping floating point value.

• Returns a copy stamping string value.

• Compares two strings, ignoring case.

• Returns 1 if a string matches a pattern, ignoring case.

• Returns the concatenation of two strings.

• Compares two strings.

• Duplicates a string.

• Strips non-essential characters from the string representation of a matrix or vector.

• Returns the number of characters in a string.

• Returns 1 if a string matches a pattern, including case.

• Replaces substrings with a new string.

• Returns one component of a string split by some separators.

• Returns the number of components in a string split by some separators.

• Generates spatially coherent 3D noise based on sparse convolution.

• Returns a substring of a string.

• Returns the length of the 3D curve between two points on a surface.

• Runs a system command line and returns the output.

• Runs a system command line and returns the exit status.

• Runs a system command line and returns the output with no processing.

• Returns the tangent of the argument.

• Returns the hyperbolic tangent of the argument.

• Returns the interpolated color of a point on an on-disk texture map.

• Returns the non-interpolated color of a point on an on-disk texture map.

• Returns the all-lowercase version of a string.

• Returns the all-uppercase version of a string.

• Takes X, Y, and Z translation values and returns a translation matrix.

• Transposes a matrix.

• Converts a number to an integer by truncating any fractional part, rounding towards 0.

• Generates spatially coherent 3D noise.

• Returns a unique value of an integer attribute.

• Returns a unique value of a string attribute.

• Converts real UV to unit UV.

• Returns the distance between parameteric locations on two primitives.

• Returns the angle between two vectors.

• Converts a string specification into a vector.

• Converts three values into a 3-component vector.

• Converts four values into a 4-component vector.

• Returns the value of a vertex attribute.

• Returns a space-separated list of vertex attribute names.

• Returns the number of components in a vertex attribute.

• Returns the type of a vertex attribute.

• Returns the list of vertex groups in a surface node.

• Returns the list of vertex groups matching a pattern in a surface node.

• Returns the string value of a vertex attribute.

• Returns a string from a list of strings in a vertex attribute.

• Returns the number of unique strings bound to a point attribute.

• Returns components of a string array attribute.

• Returns the length of a vector.

• Channel segment function: matches the incoming and outgoing slopes.

• Channel segment function: matches the incoming slope.

• Channel segment function: matches the outgoing slope.

• Returns the average value of all the voxels in a volume.

• Returns the gradient of a volume primitive at a specified location.

• Returns the value of a volume primitive at a specified voxel.

• Converts volume voxel coordinates to world-space coordinates.

• Returns the maximum value of all voxels in a volume.

• Returns the minimum value of all voxels in a volume.

• Converts world space coordinates to volume voxel coordinates.

• Returns the resolution of a volume.

• Returns the value of a volume at a specified position.

• Returns the approximage diameter of a volume voxel in world space.

• Returns a vector of an objects' transforms.

• Takes a viewer name and a viewport number and returns the viewport’s name.

• Returns a vector of an object’s rotations.

• Multiplies a vector by a scaling factor.

• Creates a vector with each component set to the same value.

• Returns the number of elements in a vector.

• Returns a vector of an object’s translations.

• Wraps a value between a minimum and maximum.

• Returns the distance between a 3D coordinate and a primitive.