Houdini 18.0 Executing Tasks

pdg package

The classes and functions in the Python pdg package for working with dependency graphs.

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Package-level functions

The following top-level attribute functions are designed to be used in Python expressions. You can use pdg.workItem() to get the current work item object in a Python expression. The top-level function floatData(work_item, "foo", 0) is equivalent to work_item.floatAttribValue("foo", 0), which is equivalent to the HScript expression @foo.

Floats

Integers

Strings

Utilities

Expression functions

API

attributes

cooking

data

events

exceptions

  • pdg.AttribError

    Generic exception raised when an error occurs when accessing work item attributes

  • pdg.CookError

    Generic exception raised when an error running the graph.

  • pdg.ServiceError

    Generic exception raised when an error occurs during a PDG service manager operation

expressions

  • pdg.EvaluationContext

    A module with global functions that operate on the thread-local evaluation context

nodes

schedulers

services

types

  • pdg.TypeRegistry

    Object containing registry of all custom node, work item, and scheduler types.

  • pdg.cacheResult

    The enumeration of cache results that can be returned by a custom cache handler

  • pdg.language

    The enumeration of languages used to define custom PDG types

  • pdg.registeredType

    The type of object when registering a custom class with PDG

  • pdg.result

    The return type of a node callback implementation

  • pdg.scheduleResult

    The return type of a scheduler’s onScheduler callback implementation

  • pdg.tickResult

    The return type of a onTick callback

workitems

Executing Tasks

Basics

Next steps

Reference

  • All TOPs nodes

    TOP nodes define a workflow where data is fed into the network, turned into "work items" and manipulated by different nodes. Many nodes represent external processes that can be run on the local machine or a server farm.

  • Processor Node Callbacks

    Processor nodes generate work items that can be executed by a scheduler

  • Partitioner Node Callbacks

    Partitioner nodes group multiple upstream work items into single partitions.

  • Scheduler Node Callbacks

    Scheduler nodes execute work items

  • Custom File Tags and Cache Handlers

    PDG uses file tags to determine the type of an output file.

  • Python API

    The classes and functions in the Python pdg package for working with dependency graphs.