Houdini 20.0 Nodes APEX Nodes

Atan2

Computes the inverse tangent of y/x.

On this page	Inputs Outputs
Since	20.0

Returns the inverse tangent of y/x, using the signs of x and y to determine the quadrant of the result. The result value is in the range -π to π.

Given a point (x, y) in the plane, the result corresponds to the angle, in radians, between the positive x-axis and the ray connecting the origin to the point (x, y). Positive angles are returned for test points in quadrants I and II, while negative angles are returned for test points in quadrants III and IV.

Inputs ¶


                x:
                    Float

The x coordinate of the test point.


                y:
                    Float

The y coordinate of the test point.

Outputs ¶


                result:
                    Float

The angle, in radians, representing the inverse tangent of y/x. The angle in the range -π to π.

See also

APEX Nodes

Abs

Computes the absolute value.
AbstractControl

Defines an abstract control in a rig.
Acos

Computes the inverse cosine.
Add

Calculates the sum of the input values.
AlmostEquals

Check if two values are almost equal.
And

Performs a logical AND operation.
Asin

Computes the inverse sine.
Atan

Computes the inverse tangent.
Atan2

Computes the inverse tangent of y/x.
Average

Computes the average of the input values.
BoolToIntBitMask
Clamp

Clamp a value between min and max.
Convert

Converts an input of type SrcT to an output of type DesT.
CopyArg

Copy the input argument.
Cosine

Computes the cosine of an angle.
CrossProduct

Compute the cross product of two vectors.
DegreesToRadians

Convert an angle in degrees to radians.
Distance

Returns the euclidean distance between two vectors.
Divide

Calculates the quotient of the input values.
DotProduct

Computes the dot product of two vectors.
DragPlane

Intersects a ray with a plane.
Equals

Returns if two values are equal.
Exponent

Raise a value to an exponent.
FloatToVector2

Build a Vector2 from Floats.
FloatToVector3

Build a Vector3 from Floats.
FloatToVector4

Build a Vector4 from Floats.
ForBegin

Defines the start of a for loop.
ForEachBegin

Defines the start of a for-each loop.
ForEachEnd

Define the end of a for each loop.
ForEnd

Defines the end of a for loop.
GetComponent

Extracts a single component of a vector or matrix type.
GreaterThan

Greater than comparison operator.
GreaterThanOrEqual

Less than or equal comparison operation.
IfBegin

Defines the start of an If block for conditional execution.
IfEnd

Defines the end of an If block for conditional execution.
IntBitMaskToBool
Invert

Inverts the matrix.
Length

Computes the length of a vector.
Lerp

Performs linear interpolation between the input values.
LessThan

Less than comparison operation.
LessThanOrEqual

Less than or equal comparison operation.
Matrix3ToVector3

Extracts the row vectors from the matrix m.
Matrix4ToVector4

Extracts the row vectors from the matrix m.
Modulo

Applies the modulo operation to the two input values.
Multiply

Calculates the product of the input values.
NLerp

Normalized lerp.
Noise

Produces Perlin-style non-periodic noise.
Normalize

Normalizes a vector.
Not

Inverts the logical value.
Null

Utility node for passing through unmodified values
Or

Performs a logical OR operation.
RadiansToDegrees

Convert an angle in radians to degrees.
RunVex

Executes a vex snippet.
SetComponent

Sets a single component of a vector or matrix type.
Sine

Computes the sine of an angle.
Subtract

Calculates the difference of the input values.
Switch

Switches between multiple input values based on an index.
SwitchByName

Switches between multiple input values based on the name of the input port.
Tan

Computes the tangent of an angle.
TransformObject

An object to represent and build a hierarchy of transformations in a rig.
TwoWaySwitch

Switches between two inputs based on a Bool value
Value

Holds a copy of an input value.
Vector2ToFloat

Extracts all the components of a vector.
Vector3ToFloat

Extracts all the components of a vector.
Vector3ToMatrix3

Constructs a matrix from the input row vectors.
Vector4ToFloat

Extracts all the components of a vector.
Vector4ToMatrix4

Constructs a matrix from the input row vectors.
Xor

Performs a logical XOR operation.
array::Add

Adds two arrays element-wise.
array::Append

Appends a value to an array.
array::Build

Builds an array with the provided values.
array::Clear

Clears an array.
array::Divide

Divides two arrays element-wise.
array::Extend

Extends an array with another array.
array::Find

Finds the index of an array element with a specific value.
array::Get

Gets an element in an array.
array::Insert

Inserts an element at a specific array index.
array::Length

Returns the length of an array.
array::Lerp

Performs linear interpolation between two arrays element-wise.
array::Max

Finds the maximum element in an array.
array::Min

Finds the minimum element in an array.
array::Multiply

Multiplies two arrays element-wise.
array::Remove

Removes an element from an array.
array::Reverse

Reverses the order of elements in an array.
array::Scale

Scales all elements of an array by a scalar.
array::Set

Sets an element in an array.
array::Sort

Sorts an array in ascending order.
array::Subtract

Subtracts two arrays element-wise.
array::Sum

Finds the sum of the array elements.
ch::AddKey

Adds a key to a channel.
ch::AddKeys

Adds keys to channels in a collection.
ch::ChannelCollectionFromPrims
ch::ChannelFromPrim
ch::ChannelToPoints

Adds a channel to a geometry as a curve or collection of points.
ch::ChannelToPrim

Adds a channel primitive to a geometry.
ch::ChannelsFromPrims
ch::CollectionReduceKeys
ch::CycleKeys

Adds additional cycles of a channel.
ch::DictUpdateFromChannelGeo

Evaluates a collection of channels and updates a dictionary with the results.
ch::Evaluate
ch::EvaluateLayered
ch::EvaluateMulti
ch::PrimsFromChannelCollection

Adds channels from a channel collection to a geometry.
ch::ReduceKeys
ch::ScaleKeys

Scales the key values of a channel about a pivot.
ch::ShiftKeys

Shifts all the keys of a channel by a constant time.
dict::Build

Copies a dictionary and adds new entries.
dict::DebugDataIds

Creates a dictionary with the data IDs of the entries of an input dictionary.
dict::Extract

Extracts multiple values from a dictionary.
dict::Get

Gets a value from a dictionary.
dict::Insert

Adds new entries to a dictionary.
dict::Keys

Gets an array of the keys of a dictionary.
dict::Remove

Removes from a dictionary all entries with keys matching a pattern.
dict::RenameKeys

Renames the keys of a dictionary.
dict::Set

Sets a value into a dictionary.
dict::Transfer

Copies entries from one dictionary to another, using a third dictionary to define the key mapping.
dict::Update

Updates the entries of a dictionary with the entries of other dictionaries.
dynamicpath::Bake
dynamicpath::Evaluate
dynamicpath::EvaluateInSourceTime
dynamicpath::EvaluateMulti
dynamicpath::EvaluateMultiInSourceTime
dynamicpath::GetAllSections
dynamicpath::GetKeyTimes
dynamicpath::GetSection
dynamicpath::GetTiming
dynamicpath::LoadFromArray
dynamicpath::LoadFromChannels
dynamicpath::LoadFromGeometry
dynamicpath::LoadFromGraph
dynamicpath::LoadFromGraphChannels
dynamicpath::ProjectileLifeFromPlane
dynamicpath::ProjectilePathEvaluatePeak
dynamicpath::ProjectilePathFromLife
dynamicpath::ProjectilePathFromPlane
dynamicpath::ProjectilePathFromSpeed
dynamicpath::WriteToGeometry
fbik::GetBoneTransform

Gets the transform of a bone on a FBIK skeleton by name.
fbik::PhysIKSolver

Creates a PhysIKSolver from a FBIK skeleton.
fbik::SetComTarget

Sets the center of mass target on an FBIK solver.
fbik::SetSkeleton

Sets the skeleton on an FBIK solver.
fbik::SetTarget

Set a target on an FBIK solver with a bone name.
fbik::SetTargets

Sets multiple targets on an FBIK solver.
fbik::SetTargetsFromDict

Sets targets on an FBIK solver from a Dict.
fbik::SkeletonFromGeo

Gets a FBIK skeleton stored in geometry.
fbik::SkeletonUpdateGeo

Update geometry according to an FBIK skeleton.
fbik::SolvePhysIK

Solves an FBIK skeleton using using a solver.
fbik::Target

Creates a FBIK skeleton target.
geo::AddPacked

Create a new packed primitive that uses the given embedded geometry.
geo::ArrayAttribValue

Return the attribute value for a particular array attribute.
geo::AttribIntersectPoints
geo::DetailAttribValue

Return the detail attribute value for a particular attribute.
geo::DisplacePoints
geo::DragPoints
geo::ExtractPackedGeo

Returns the geometry embedded in a packed primitive.
geo::FindPointAttribValue

Look up all points in a geometry that have a particular attribute value.
geo::FindPrimAttribValue

Look up all primitives in a geometry that have a particular attribute value.
geo::FindVertexAttribValue

Look up all vertices in a geometry that have a particular attribute value.
geo::ForEachPointBegin

Define the start of a for each point loop.
geo::ForEachPointEnd

Define the end of a for each point loop.
geo::ForEachPrimBegin

Define the start of a for each primitive loop.
geo::ForEachPrimEnd

Define the end of a for each primitive loop.
geo::FromDisk

Specify a geometry file to read in from disk.
geo::GlobPoints

Return an array of points corresponding to a pattern of point numbers.
geo::GlobPrims

Return an array of primitives corresponding to a pattern of primitive numbers.
geo::InitIntersectCache

Compute an intersection cache for a geometry.
geo::Intersect

Determines the intersection point of a ray with an intersection cache.
geo::IntersectPoints
geo::Merge

Merge the points and primitives from other geometry object into this one.
geo::MergePacked

Pack each input and merge all of them together into a single geometry.
geo::NumPoints

Return the number of points in a geometry.
geo::NumPrims

Return the number of primitives in a geometry.
geo::PointAttribValue

Return the point attribute value for a particular attribute.
geo::PointPrims

Returns all primitives containing a point.
geo::PrimAttribValue

Return the primitive attribute value for a particular attribute.
geo::PrimPoints

Returns all points on a primitive.
geo::Replace

Replace the contents of a geometry object with another’s.
geo::SetAgentTransforms

Overrides the transforms of an agent primitive.
geo::SetDetailAttribValue

Set a detail attribute value.
geo::SetPointAttribValue

Set a point attribute value.
geo::SetPointAttribValues

For a particular attribute, set the attribute values for all points.
geo::SetPointAttribValuesByName

For a particular attribute, look up points on the geometry by name and set their attribute values.
geo::SetPrimAttribValue

Set a primitive attribute value.
geo::SetPrimAttribValues

For a particular attribute, set the attribute values for all primitives.
geo::SetPrimAttribValuesByName

For a particular attribute, look up primitives on the geometry by name and set their attribute values.
geo::SetVertexAttribValue

Set a vertex attribute value.
geo::SetVertexAttribValues

For a particular attribute, set the attribute values for all vertices.
geo::SetVertexAttribValuesByName

For a particular attribute, look up vertices on the geometry by name and set their attribute values.
geo::SmoothPoints
geo::Transform

Transforms (e.g. rotates, scales, translates, etc.) the geometry by a transformation matrix
geo::UpdatePackedGeo

Embeds the provided geometry into a packed primitive, replacing its contents.
geo::VertexAttribValue

Return the vertex attribute value for a particular attribute.
graph::AddNode

Adds an APEX node with a specific name and node type to the provided APEX Graph.
graph::AddSubnet

Adds an APEX subnet node to a given APEX graph and add sets the contents of a given APEX graph as its content.
graph::AddSubnetNew
graph::Compile
graph::ConnectInput

Connects two APEX node ports together by adding a wire.
graph::DeleteNode

Deletes a given node from the APEX graph.
graph::DeleteNodes
graph::EvaluateOutputs
graph::FindAndConnectInput

Connects two APEX node with specified port names together with a wire. The ports must be from two different nodes.
graph::FindNode

Finds an APEX node id in a given APEX graph based on a node path.
graph::FindNodeInput

Finds an APEX port id for a given output port defined by a name on a specified APEX node.
graph::FindNodeOutput

Finds an APEX port id for a given input port defined by a name on a specified APEX node.
graph::FindNodes

Finds an array of APEX node ids in a given APEX graph based on a node pattern.
graph::FindOrAddNode

Finds or add an APEX node with a specific name and node type to the provided APEX Graph.
graph::FindOrAddPort

Finds or adds an APEX port or subport of an APEX node based on a port name.
graph::FindPort

Finds an APEX port of an APEX node based on a port name
graph::FindPorts

Finds an array of APEX port ids in a given APEX graph based on a port pattern.
graph::GetCompiledParms
graph::GetConnectedNodes

Finds all APEX nodes that are have a direct wire connection to a given APEX port.
graph::GetConnectedPorts

Finds all APEX port that are have a direct wire connection to a given APEX port.
graph::GetPromotedPort

Finds the promted APEX graph input or output port that is connected with a given APEX port
graph::GetSubPort

Finds or adds an APEX subport to a given APEX port based on a subport port name.
graph::GraphInputs

Finds all top level parm input ports of a given APEX graph.
graph::GraphOutputs

Finds all top level output APEX ports of a given APEX graph.
graph::Invoke
graph::IsConnected

Returns if a given parm input port is connected when the given APEX graph is being used as a subgraph.
graph::Layout

Creates a default positional layout of all of a given selection of APEX nodes.
graph::LoadFromGeo

Load an APEX graph from geometry.
graph::Merge

Merges the contents of a APEX graphs into an existing APEX graph.
graph::NodeData
graph::NodeInputs

Finds all the available input port ids for a given APEX node.
graph::NodeOutputs

Finds all the available output port ids for a given APEX node.
graph::PackSubnet

Packs a given array of APEX nodes of a given APEX graph into a subnet, keeping all existing connections.
graph::PortData
graph::PortNode
graph::PromoteInput

Link a port to an APEX graph input.
graph::PromoteOutput

Link a port to an APEX graph output.
graph::RewireOutputs

Rewire output ports on an APEX node in an APEX graph.
graph::SetCompiledParms
graph::Sort

Sort an APEX graph.
graph::UnpackSubnet

Unpack a subnet in an APEX graph.
graph::UpdateNode

Update an APEX node in an APEX graph.
graph::UpdateNodeParms

Update parms on an APEX node in an APEX graph.
graph::UpdateNodeProperties

Update properties on an APEX node in an APEX graph.
graph::UpdateNodeTags

Update tags on an APEX node in an APEX graph.
graph::WriteToGeo

Write an APEX graph to geometry.
quaternion::Distance

Finds distance between two quaternions.
quaternion::FromAxisAngle

Creates a Vector4 representing a unit quaternion from an angle and an axis.
quaternion::FromEuler

Creates a Vector4 representing a quaternion from euler angles.
quaternion::FromMatrix

Converts a rotation matrix into a unit quaternion.
quaternion::Invert

Inverts a quaternion.
quaternion::Multiply

Multiplies two quaternions and returns the result.
quaternion::Rotate

Rotates a vector by a given quaternion.
quaternion::SwingTwistDecompose

Decomposes a quaternion into a twist along an axis and a swing.
quaternion::SwingTwistInterpolate

Interpolates between two quaternions while interpolating the the swing and twist components separately.
quaternion::ToAxisAngle

Converts a quaternion represented by a vector4 into an axis vector and an angle.
quaternion::ToEuler

Creates an euler angle representing a quaternion.
quaternion::ToMatrix

Converts a quaternion to a rotation or transformation matrix.
rig::CombineParmTransform

Combines an input transform matrix and a set of translation, rotation and scale parameters into a new transform.
rig::ControlSpline

Create a spline of the given order using the given list of CVs.
rig::ControlSplineFromArray

Create a spline of the given order using the given array of CVs.
rig::CurveConstraint

Outputs a transform matrix derived from a location on a curve primitive.
rig::CurveIK
rig::ExtractLocalTransform

Extracts a local transform given a child and parent transform, taking scale inheritance rules into account.
rig::ExtractParmTransform
rig::FkTransform
rig::ParentBlend
rig::PointConstraint

Computes a transform from a weighted mix of points on a Geometry.
rig::PoseWeightInterpolation
rig::RBFInterpolation
rig::SampleSplineTransforms

Sample transforms from a spline.
rig::SampleSplineTransformsToArray

Sample transforms from a spline.
rig::SplineInterpolateTransforms
rig::SplineInterpolateTransformsArray
rig::TwoBoneIK
rig::UVConstraint
sim::CreateObject

Adds a new dynamics object to a simulation.
sim::CreateRelationship

Adds a new dynamics relationship to a simulation.
sim::CreateSubData

Attaches data to a simulation object or relationship.
sim::EvaluateAtTime
sim::FindObject
sim::FindRelationship
sim::GetGeometry
sim::LoadSimFile

Loads a simulation state from a file.
sim::RemoveObject

Removes an object from a simulation.
sim::RemoveRelationship

Removes a relationship from a simulation.
sim::SetGeometry

Modifies geometry subdata for a simulation object or relationship.
sim::SimEngine
skel::AddJoint

Create a new KineFX point on the geometry.
skel::DeleteJoint

Delete a KineFX point from the geometry.
skel::DeleteJoints

Delete a group of KineFX points from the geometry.
skel::EvaluateMotionClipArray

Evaluate a single pose from multiple MotionClips.
skel::FindJoint

Find a KineFX point by its name attribute.
skel::FindRoots

Find all KineFX points that do not have a parent.
skel::GetAncestors

Find all ancestors of a specific KineFX point.
skel::GetChildren

Find all children of a specific KineFX point.
skel::GetDescendants

Find all descendants of a specific KineFX point.
skel::GetParent

Find the parent of a specific KineFX point.
skel::GetPointLocalTransform

Return the local transform attribute value of a KineFX point.
skel::GetPointTransform

Return the world transform of a KineFX point.
skel::GetPointTransforms

Return the world transforms from multiple KineFX points.
skel::SetParent

Set a new parent for a KineFX point.
skel::SetParents

Set new parents for multiple KineFX points.
skel::SetPointTransforms

Set the world transforms of multiple KineFX points.
skel::SetPointTransformsFromAgent

Set the world transforms of multiple KineFX points from an agent.
skel::Sort

Sort the KineFX points in the geometry based on their hierarchy.
skel::Traverse

Traverse the whole KineFX hierarchy and write out the result.
skel::UpdateJoint

Update the attribute values of a KineFX point.
string::Format
string::FromInteger

Convert an integer to string
string::FromRamp

Converts a ramp to a string.
string::Length

Compute the length of a string
string::Replace
string::Split

Splits a string into multiple tokens
string::ToRamp

Converts a string to a ramp.
transform::Blend

Blends between two matrices.
transform::Build
transform::Determinant
transform::Dihedral
transform::Explode
transform::LookAt

Rotates a 4×4 matrix so its -Z axis points at a target.
transform::MultiBlend

Blend multiple matrices or quaternions based on multiple weights.
transform::MultiBlendFromArray

Blend an array of matrices or quaternions based on a weights array.
transform::PolarDecompose
transform::Prerotate

Applies a prerotation to the given matrix.
transform::Prescale

Prescales the given matrix in three directions simultaneously by the components of a vector.
transform::Pretranslate

Pretranslates a matrix by a vector.
transform::Rotate

Applies a rotation to the given matrix.
transform::RotateAboutAxis
transform::Scale

Scales the given matrix in three directions simultaneously by the components of a vector.
transform::Slerp

Performs spherical linear interpolation.
transform::SmoothRotation
transform::Translate

Translates a matrix by a vector.