hou module

Module containing all the sub-modules, classes, and functions to access Houdini.

Subtopics

Filter by title

Categories: Channels, Cooking, Digital assets, Dynamics, Exceptions, Files and IO, General, Geometry, Images, Keyframes, Materials, Nodes, Nodes: organization, Nodes: type categories, Objects, Parameter templates, Parameters, Rendering, Scripting, Shelf, Takes, Timeline, User interface, Utility, VEX, Viewer

Digital assets

hou.HDADefinition class

hou.HDAModule class

User-defined module containing common functions, classes, and constants that can be used by scripts of an HDA, expressions in parameters of nodes in the HDA, etc.

hou.HDAOptions class

hou.HDASection class

hou.hdaNodeTypes function

This is not implemented yet

hou.hda module

Channels

hou.ChannelDopesheet class

hou.ChannelEditorPane class

hou.ChannelGraphEditor class

hou.ChannelList class

hou.ChannelListPane class

hou.ChopNode class

Class representing a CHOP node.

hou.ChopViewerPane class

hou.Track class

hou.bezier function

Evaluate a Bezier interpolation spline for an animated parameter using the left keyframe’s outgoing value, tangent, and acceleration and the right keyframe’s incoming value, tangent, and acceleration.

hou.commitPendingKeyframes function

This is not implemented yet

hou.constant function

Evaluate an animation function for an animated parameter. The return value is always the left keyframe’s outgoing value.

hou.cubic function

Evaluate an interpolation function for an animated parameter that gives a smooth curve between the left keyframe’s outgoing value and the right keyframe’s incoming value, using the left’s outgoing slope and the right’s incoming slope.

hou.cycle function

This animation function for an animated parameter repeats the motion between two frames, lining up the first repeated value with the left keyframe’s value.

hou.cyclet function

This animation function for an animated parameter repeats the motion between two times, lining up the repeated values with the left keyframe’s value.

hou.ease function

This animation function for an animated parameter interpolates between the left keyframe’s outgoing value and the right keyframe’s incoming value. The tangents will be flat at both ends of the function, so the curve will slowly ease from the left value and, near the end of the function, slowly reduce the speed until it is at rest at the right value.

hou.easein function

This animation function for an animated parameter interpolates between the left keyframe’s outgoing value and the right keyframe’s incoming value. The tangent will be flat at the left end of the function, so it will slowly ease from the outgoing value of the left keyframe.

hou.easeinp function

This animation function for an animated parameter interpolates between the values of two keyframes. It is like hou.easein(), except it has an additional parameter to say how fast the curve should ease into the motion.

hou.easeout function

This animation function for an animated parameter interpolates between the left keyframe’s outgoing value and the right keyframe’s incoming value. The tangent will be flat at the right end of the function, so it will slowly come to rest at the incoming value of the right keyframe.

hou.easeoutp function

This animation function for an animated parameter interpolates between the values of two keyframes. It is like hou.easeout(), except it has an additional parameter to say how fast the curve should ease into the motion.

hou.easep function

This animation function for an animated parameter interpolates between the values of two keyframes. An ease bias of less than one slow the animation near right keyframe, while an ease bias greater than one will slow it near the left keyframe.

hou.linear function

This animation function for an animated parameter linearly interpolates between the left keyframe’s outgoing value and the right keyframe’s incoming value.

hou.match function

This animation function for an animated parameter creates a smooth curve between the left keyframe’s incoming value and the right keyframe’s outgoing value, using the left keyframe’s incoming slope and the right keyframe’s outgoing slope.

hou.matchin function

This animation function for an animated parameter creates a straight line from the left keyframe’s incoming value, matching the left keyframe’s incoming slope. The line will not match the right keyframe’s outgoing value.

hou.matchout function

This animation function for an animated parameter creates a straight line from the right keyframe’s outgoing value, matching the right keyframe’s outgoing slope. The line will not match the left keyframe’s incoming value.

hou.qlinear function

This animation function for an animated parameter linearly interpolates between keyframes using quaternions. The neighbouring parameters must also be animated; for example, if “rx” uses qlinear(), “ry” and “rz” should also use qlinear().

hou.quintic function

hou.repeat function

This animation function for an animated parameter repeats the motion between two times.

hou.repeatt function

This animation function for an animated parameter repeats the motion between two times.

hou.spline function

This animation function for an animated parameter fits a spline through consecutive keyframe values that also use the hou.spline() function. The resulting spline interpolates the channel values at the keyframes, and slope values are not used.

hou.vmatch function

This animation function for an animated parameter matches the incoming and outgoing values and slopes. Unlike the hou.match() function, it will use its left keyframe’s outgoing value and the right keyframe’s incoming value, so hou.vmatch() can produce curves that are discontinuous with the previous segment.

hou.vmatchin function

This animation function for an animated parameter matches the left keyframe’s incoming slope. The curve will be a straight line from the left keyframe’s outgoing value, and will not match the right keyframe’s outgoing value. Unlike the hou.matchin() function, the left keyframe’s outgoing value can differ from its incoming value, so so hou.vmatchin() can produce curves whose left tangent matches the left keyframe but whose left values do not line up.

hou.vmatchout function

This animation function for an animated parameter matches the right keyframe’s outgoing slope. The curve will be a straight line ending at the right keyframe’s incoming value, and will not match the left keyframe’s incoming value. Unlike the hou.matchout() function, the right keyframe’s incoming value can differ from its outgoing value, so so hou.vmatchout() can produce curves whose right tangent matches the right keyframe but whose right values do not line up.

Cooking

hou.recookNodesIfReferencedFilesChanged function

This is not implemented yet

hou.setHighlightNodesWhenCooking function

This is not implemented yet

hou.showCookStatisticsInNodeInfo function

This is not implemented yet

hou.performance module

Dynamics

hou.DopData class

hou.DopDataRecord class

hou.DopDataRecordType class

hou.DopDataType class

hou.DopField class

hou.DopFieldComponent class

hou.DopNetNode class

hou.DopNode class

Class representing a DOP node.

hou.DopObject class

hou.DopObjectGroup class

hou.DopRecord class

hou.DopRelationship class

hou.DopSimulation class

hou.currentDopNet function

This is not documented yet

hou.dopDataTypes function

This is not implemented yet

hou.setCurrentDopNet function

This is not documented yet

hou.simulationEnabled function

This is not documented yet

hou.setSimulationEnabled method

This is not documented yet

hou.dop module

hou.fieldType module

Exceptions

hou.Error class

Base class for all exceptions in the hou module.

hou.GeometryPermissionError class

hou.InitScriptFailed class

hou.InvalidInput class

hou.InvalidNodeName class

hou.InvalidNodeType class

hou.InvalidSize class

hou.KeyframeValueNotSet class

hou.LoadWarning class

Exception class for when loading a hip file in Houdini generates warnings. This class is a subclass of hou.Error.

hou.MatchDefinitionError class

hou.NotAvailable class

Exception class for when an operation attempted to use a feature that is not available. This class is a subclass of hou.Error.

hou.ObjectWasDeleted class

Exception class for when you use a stale variable to attempt to access something that was deleted in Houdini. This class is a subclass of hou.Error.

hou.OperationFailed class

hou.OperationInterrupted class

hou.PermissionError class

hou.SystemExit class

hou.TypeError class

hou.ValueError class

General

hou.EnumValue class

This class is the base class for an enumeration value. It cannot be instanced and is not meant to be used directly by the user.

hou.Preference class

This is not implemented yet.

hou.Value class

This is not implemented yet.

hou.Variable class

This is not implemented yet.

hou._isExiting function

Returns whether Houdini is in the process of exiting. This function is called internally by the interactive Houdini Python shell.

hou.almostEqual function

Compares two numbers and returns True if they are almost equal in terms of how far apart they are when represented as floating point numbers.

hou.appendSessionModuleSource function

Appends the given source code to the hou.session module. The appended code is made available immediately. You do not have to re-import hou.session.

hou.applicationCompilationDate function

Returns the application’s compilation date.

hou.applicationName function

Returns the application name.

hou.applicationVersion function

Returns the application’s version number as a tuple of integers – (major_version, minor_version, build_version).

hou.applicationVersionString function

Returns the application’s version number as a string.

hou.convertToNewKinematics function

This is not implemented yet

hou.createVariable function

This is not implemented yet

hou.exit function

Exits Houdini, returning the exit code to the operating system. If suppress_save_prompt is false, this function asks the user if he/she wants to save. If the user presses “Cancel”, the exit will be canceled and the next statement will execute.

hou.isApprentice function

Returns True if the application is an apprentice (non-commercial) version. Returns False otherwise.

hou.operatingSystem function

This is not implemented yet

hou.releaseLicense function

Release the currently held Houdini license.

hou.sessionModuleSource function

Returns the contents of the hou.session module.

hou.setSessionModuleSource function

Sets the contents of the hou.session module. The new contents is made available immediately. You do not have to re-import hou.session.

hou.variable function

This is not implemented yet

hou.variables function

This is not implemented yet

hou.audio module

This is not implemented yet.

hou.cache module

This is not implemented yet.

hou.hipFile module

hou.hmath module

Module containing Houdini math functions

hou.session module

This module is used to define custom classes, functions and variables that can be called from within the current Houdini session. The contents of this module are saved into the .hip file.

Geometry

hou.Attrib class

hou.BezierSurface class

hou.Curve class

hou.CurvedSurface class

hou.Face class

hou.Geometry class

hou.Mesh class

hou.Metaball class

hou.NURBSCurve class

hou.NURBSSurface class

hou.Point class

hou.PointGroup class

hou.Polygon class

hou.Prim class

hou.PrimGroup class

hou.Quadric class

hou.SopCacheWatermark class

hou.SopNode class

Class representing a SOP node.

hou.Surface class

hou.Vertex class

hou.Volume class

attribData module

Module containing enumerated values for the different attribute data types.

hou.attribType module

hou.geometryType module

hou.primType module

Files and IO

hou.DirectorySearchPath class

hou.FileType class

hou.fileReferences function

This is not implemented yet

hou.findDirectories function

Search the houdini path for the specified directory, returning a tuple of all the matches. The directory name specified should be relative to the houdini directory.

hou.findDirectory function

Search the houdini path for a specified directory, returning the first match found. The directory name specified should be relative to the houdini directory.

hou.findFile function

Search the houdini path for a specified file, returning the first match found. The filename specified should be relative to the houdini directory.

hou.findFiles function

Search the houdini path for the specified file, returning a tuple of all the matches. The filename specified should be relative to the houdini directory.

hou.hfile function

This is not implemented yet

hou.houdiniPath function

This is not implemented yet

hou.readFile function

Read a file, returning the contents in a string. Supports regular files, opdef: and oplib: paths, and http URLs.

hou.knownFileTypes module

Images

hou.CompositorViewer class

hou.CopNode class

hou.HistogramViewer class

hou.ImageTimelineViewer class

hou.ImageViewer class

hou.ModalImageViewer class

hou.Mplay class

hou.pixelColourInFileByUV function

This is not implemented yet

Keyframes

hou.BaseKeyframe class

Abstract base class for all keyframe class.

hou.Keyframe class

Class representing the default keyframe type, a numerical keyframe.

hou.StringKeyframe class

hou.infoAboutParmKeyframeFile function

This is not implemented yet

hou.loadParmKeyframes function

This is not implemented yet

hou.saveParmKeyframes function

This is not implemented yet

hou.setDefaultSegmentFunction function

This is not implemented yet

Materials

hou.Gallery class

hou.GalleryEntry class

hou.ShopNode class

Class representing a SHOP node.

hou.galleries module

hou.shaderType module

Nodes: organization

hou.NetworkBox class

hou.NodeBundle class

hou.NodeGroup class

hou.addNodeBundle function

This is not implemented yet

hou.findNodeBundle function

This is not implemented yet

hou.nodeBundles function

This is not implemented yet

hou.saveNetworkBoxesToFile function

This is not implemented yet

hou.nodeTypeFilter module

Nodes: type categories

hou.NodeTypeCategory class

Class representing a category of node types.

hou.ShopNodeTypeCategory class

hou.chopNetNodeTypeCategory function

Return the NodeTypeCategory instance for Houdini channel container (chopnet) nodes.

hou.chopNodeTypeCategory function

Return the NodeTypeCategory instance for Houdini channel (chop) nodes.

hou.cop2NetNodeTypeCategory function

Return the NodeTypeCategory instance for Houdini composite container (copnet) nodes.

hou.cop2NodeTypeCategory function

Return the NodeTypeCategory instance for Houdini composite (cop) nodes.

hou.dopNodeTypeCategory function

Return the NodeTypeCategory instance for Houdini dynamic (dop) nodes.

hou.managerNodeTypeCategory function

Return the NodeTypeCategory instance for Houdini manager nodes. The manager nodes are /obj, /out, /part, /ch, /shop, /img, and /vex.

hou.nodeTypeCategories function

Returns a dictionary of node type categories where the keys are the category names (i.e. “Object”, “Sop”, etc.) and the values are hou.NodeTypeCategory objects.

hou.nodeTypeCategory function

This is not implemented yet

hou.objNodeTypeCategory function

Return the NodeTypeCategory instance for Houdini object nodes. For example, if /obj/model is an object, hou.node(“/obj/model”).nodeTypeCategory() == hou.objectNodeTypeCategory() will return True.

hou.popNetNodeTypeCategory function

Return the NodeTypeCategory instance for Houdini particle container (popnet) nodes.

hou.popNodeTypeCategory function

Return the NodeTypeCategory instance for Houdini particle (pop) nodes.

hou.rootNodeTypeCategory function

Return the NodeTypeCategory instance for Houdini root (/) node. There is only one instance of the root node, and it has its own node type category.

hou.ropNodeTypeCategory function

Return the NodeTypeCategory instance for Houdini output (rop) nodes.

hou.shopNodeTypeCategory function

Return the NodeTypeCategory instance for Houdini shader (shop) nodes.

hou.sopNodeTypeCategory function

Return the NodeTypeCategory instance for Houdini geometry (sop) nodes.

hou.vopNetNodeTypeCategory function

Return the NodeTypeCategory instance for Houdini vex builder container (vopnet) nodes.

hou.vopNodeTypeCategory function

Return the NodeTypeCategory instance for Houdini vex builder (vop) nodes.

Nodes

hou.Node class

Base class for all Houdini nodes. You cannot create instances of this class by calling the constructor. You can access Node objects by finding an existing node or by creating a child node from an existing node.

hou.NodeConnection class

The NodeConnection class represents a connection, or wire, between two nodes.

hou.NodeParmPresets class

hou.NodeType class

Class representing a type of a node.

hou.PopNetNode class

hou.PopNode class

Class representing a POP node.

hou.SopNodeType class

hou.SubnetIndirectInput class

hou.VopNetNode class

hou.cd function

Change the current node. Houdini has one current node, analogous to a current directory in a file system. If a relative path is given, it is relative to the node returned by hou.pwd().

hou.copyNodesTo function

Copy all given nodes to a new place in node hierarchy.

hou.copyNodesToClipboard function

This is not implemented yet

hou.currentSimulation function

This is not documented yet

hou.filterNodesByType function

This is not implemented yet

hou.layoutNodes function

This is not implemented yet

hou.loadNodesFromFile function

This is not implemented yet

hou.moveNodesTo function

Move all given nodes to a new place in node hierarchy.

hou.node function

Find a node, given either an absolute or a relative path to it. Relative path searches are done from the node returned by , so hou.node(path) is a shortcut for hou.pwd().node(path). Returns None if no node exists at that path.

hou.nodeType function

Returns a hou.NodeType object which contains information about the requested operator type. Returns None if the requested type does not exist.

hou.pasteNodesFromClipboard function

This is not implemented yet

hou.pwd function

Return the current node or the node containing the evaluating parm. Houdini has one current node, analogous to a current directory in a file system. You can change the current node with cd().

hou.root function

Return the root node (i.e. /).

hou.saveNodesToFile function

This is not implemented yet

hou.setCurrentSimulation function

This is not implemented yet

hou.setPwd function

Make the given node Houdini’s current node. This function is equivalent to hou.cd(node.path()).

hou.nodeTypeSource module

hou.perms module

Objects

hou.AmbientLightObjNode class

hou.BoneObjNode class

hou.GeometryObjNode class

hou.LightObjNode class

hou.ObjNode class

Parameters

hou.NodeReferenceParm class

hou.Parm class

Class representing a node parameter.

hou.ParmGroup class

hou.ParmTuple class

Class representing a tuple of node parameters.

hou.ch function

The same as evalParm(). Provided for backward compatibility.

hou.chsop function

Evaluate a parameter that references a node, and return the absolute path to the node.

hou.evalParm function

Evaluate a parameter, given either an absolute or a relative path to it. Relative path searches are done from the node returned by . This function is a shortcut for hou.parm(path).eval().

hou.evalParmTuple function

Evaluate a parameter, given either an absolute or a relative path to it. Relative path searches are done from the node returned by . This function is a shortcut for hou.parmTuple(path).eval().

hou.loadParmSamples function

This is not implemented yet

hou.parm function

Find a parameter, given either an absolute or a relative path to it. Relative path searches are done from the node returned by , so hou.parm(path) is a shortcut for hou.pwd().parm(path). Returns None if no parameter exists at that path.

hou.parmTuple function

Find a parameter tuple, given either an absolute or a relative path to it. Relative path searches are done from the node returned by , so hou.parmTuple(path) is a shortcut for hou.pwd().parmTuple(path). Returns None if no parameter exists at that path.

hou.saveParmSamples function

This is not implemented yet

hou.topLevelParmGroup function

This is not implemented yet

hou.exprLanguage module

hou.fileType module

hou.scope module

hou.scriptLanguage module

hou.updateMode module

Parameter templates

hou.ButtonParmTemplate class

Describes a button parameter.

hou.FileReferenceParmTemplate class

hou.FloatParmTemplate class

hou.FolderSetParmTemplate class

Describes a set of folders.

hou.IntParmTemplate class

hou.LabelParmTemplate class

Describes a label parameter.

hou.MenuParmTemplate class

hou.NodeReferenceParmTemplate class

hou.ParmTemplate class

hou.SeparatorParmTemplate class

Describes a separator parameter. Separators are just vertical lines between parameters.

hou.StringParmTemplate class

hou.ToggleParmTemplate class

hou.parmData module

hou.parmLook module

The possible looks for a parameter

hou.parmNamingScheme module

The possible naming schemes for a parameter.

hou.parmTemplateType module

hou.stringParmType module

Rendering

hou.ActiveRender class

hou.RenderMachineVariable class

hou.RopNode class

Class representing a ROP node.

hou.activeRenders function

This is not implemented yet

hou.renderMachineVariables module

hou.renderMethod module

Scripting

hou.ShellIO class

hou.Textport class

hou.TextportPane class

hou._addPreloadIcon function

This function is used internally by Houdini to preload icons for speed.

hou._getArgumentAutoComplete function

This function is used internally by the Houdini Python shell for argument auto-completion on functions of the hou module.

hou.endListeningOnPort function

This is not implemented yet

hou.exitScript function

This is not implemented yet

hou.expandString function

Evaluates the given string expression and returns the result.

hou.hscript function

Executes the given hscript command and returns a 2-tuple of strings where the first string contains the regular output of the executed command and the second string contains the error output. You can specify multiple commands by using ';' or the newline character as the separator.

hou.hscriptCommandHelp function

Return the text help of an hscript command. This function is used to help re-implement hscript commands in Python.

hou.hscriptExpandString function

Deprecated: Use expandString.

hou.hscriptExpression function

Evaluate an Hscript expression.

hou.hscriptFloatExpression function

Evaluate an Hscript expression as a float.