Houdini 17.0 Nodes Render nodes

Pre Post render node

Renders ROPs before and after a main job.

On this page

Overview

Renders the first input, then all frames of the second input, then the third input. This lets you run the "preprocessing" and "postprocessing" nodes once per job. This is useful for render jobs that use frame-interleaved rendering. If you simply connected the nodes (pre → main → post), the "pre" and "post" nodes would render before and after each frame.

For example, the following network:

…will render: pre1, pre2, pre3, mantra1, mantra2, mantra3, post1, post2, post3.

A simple chain:

…would render pre1, mantra1, post1, pre2, mantra2, post2, pre3, mantra3, post3.

Only the second (main) input is required. The "pre" and "post" connections are optional. You can also connect the inputs but then disable them with the Run pre render operation and Run post render operation, allowing you to base pre and post rendering on the value of an expression.

Note

To render multiple inputs at the same time instead of serially, use the Merge ROP.

Limitations

  • None of the inputs can refer to the same ROP, as this would cause dependency cycles.

  • The Pre render and Post render ROPs cannot branch out to meet each other or the main render branch. They must be separate, self-contained branches.

  • ROPs that are dependent on the Pre Post ROP (outputs), either directly or indirectly, should not also be dependent on any nodes in the Pre render, Main job or Post render branches. This could cause cyclic dependencies or double processing of a frame.

Essentially, each input should have its own branch which no other outside ROPs reference.

Parameters

Render

Begins the render with the last render control settings.

Render Control

Opens the render control dialog to allow adjustments of the render parameters before rendering.

Run pre render operation

When enabled, the pre render branch is performed before the main render ob.

Pre Frame Range

Allows the frame range of the Pre render ROP to be overriden.

Pre render ROP’s specified range: Use the frame range specified in the Pre render ROP. If set to Render Current Frame, it will be rendered once at the time of the first frame of the main job.

Main job’s first frame: Run the Pre render ROP once at the frame time of the first frame rendered by the main job.

Main job’s last frame: Run the Pre render ROP once at the frame time of the last frame rendered by the main job.

Main job’s frame range

Run the Pre render ROP across the frame range of the main render job.

Run Post render operation

When enabled, the Post render branch is performed after all the frames of the main render job.

Post Frame Range

Allows the frame range of the Post render ROP to be overriden.

Post render ROP’s specified range: Use the frame range specified in the Post render ROP. If set to Render Current Frame, it will be rendered once at the time of the last frame of the main job.

Main job’s first frame: Run the post-render ROP once at the frame time of the first frame rendered by the main job.

Main job’s last frame: Run the Post render ROP once at the frame time of the last frame rendered by the main job.

Main job’s frame range

Run the Post Render ROP across the frame range of the main render job.

Locals

N

Frame being rendered.

NRENDER

Total number of frames being rendered.

Render nodes

  • Agent

    This output operator is used to write agent definition files.

  • Alembic

  • Archive Generator

    Generates disk-based archives which can be used by either mantra or RIB renderers.

  • Bake Animation

    Bakes animation from object transforms and CHOP overrides.

  • Bake Texture

    Generates a texture map from one or more objects' rendered appearance.

  • Batch

    Renders the input ROP in a single batch job.

  • Brick Map Generator

    Allows you to convert Houdini volume primitives into Pixar brickmap files.

  • Channel

    The Channel output operator generates clip files from a particular CHOP.

  • Composite

    The Composite output operator renders the image(s) produced in the Compositing Editor.

  • DSM Merge

    Merges two or more deep shadow/camera map files.

  • Dynamics

    Saves the state of a DOP network simulation into files.

  • Fetch

    Makes a dependency link to a ROP in a different network.

  • Filmbox FBX

    Exports entire scenes to FBX files.

  • Frame Container

    Prevents frame dependency changes in the contained nodes from affecting its inputs.

  • Frame Depedency

    Allows an output frame to depend on one or more input frames.

  • Geometry

    Generates geometry files from a SOP or DOP network.

  • HQueue Render

    HQueue, or Houdini Queue, is a distributed job scheduling system.

  • HQueue Simulation

    HQueue, or Houdini Queue, is a distributed job scheduling system.

  • Hair Card Texture

    Renders hair textures for use on hair cards.

  • MDD Point Cache

    This output operator is used to write an MDD animation file.

  • Mantra

    Renders the scene using Houdini’s standard mantra renderer and generates IFD files.

  • Mantra Archive

    Generates disk-based archives which can be used by mantra.

  • Merge

    Merges several render dependencies into one.

  • Net Barrier

    Blocks the ROP network until synchronization occurs.

  • Null

    Does nothing.

  • OpenGL

    Render an image using the hardware-accelerated 3D viewport renderer.

  • Pre Post

    Renders ROPs before and after a main job.

  • RenderMan

    Renders the scene using Pixar’s RenderMan renderer.

  • RenderMan

    Renders the scene using Pixar’s RenderMan RIS renderer.

  • RenderMan Archive

    Generates disk-based archives which can be used by RenderMan .

  • Shell

    Runs an external command.

  • Subnetwork

    The SubNetwork output operator provides an easy way to manage large number of output operators.

  • Switch

    Renders one of several inputs.

  • Tractor

    Tractor is a program shipped out with Pixar’s distribution of RenderMan.

  • Wedge

    Re-renders the same ROP multiple times with different settings

  • Wren

    This output operator is used to drive the Wren rendering program.

  • glTF

  • glTF