Nodes Render output nodes

Render nodes are “drivers” for rendering out the scene into various formats, often using external programs. For example, the mantra node uses mantra to render the scene, while the RenderMan node uses RenderMan.

Overview

Output driver nodes translate the scene into the format expected by a renderer and run the renderer on it. Houdini includes render drivers for the built-in mantra renderer, as well as RenderMan, other RIB renderers, and mental ray.

Output driver nodes live at the Render Outputs (ROP) level. They let you set up renders for different rendering methods, programs, and/or settings, and switch between them based on your needs at any given moment.

For example, you can set up different output nodes for different render qualities (such as test render and final render) and independent render passes. Or, you can render various scenes with different renderers.

Each driver renders the view of the scene through a camera . For a driver to work correctly, the camera associated with the driver must still exist.

  • Use Render > Create Render Node to create a new output driver.

  • Use Render > Edit Render Node to select and edit an existing render driver.

Note

Houdini’s shaders are specific to particular renderers. Rendering with a different renderer will require you to use different shaders on your objects. However, you can switch shaders based on the renderer .

How to temporarily disable outputs

ROPs have bypass flags and lock flags, which you can use to disable ROPs without disconnecting them from the network.

Bypassing a ROP will stop it from rendering. Input ROPs will still render.

Locking a ROP will stop it and all its input ROPs from rendering. This is a good way to 'lock off' a branch of renders. If some input ROP has another ROP that is dependent on it, and that ROP isn’t locked, it will still render. Locking a ROP will only block the one dependency path through the locked ROP.

Bypassing or locking a subnetwork will prevent any of the ROPs inside from rendering.

Tip

You can still force a bypassed or locked render node to render using the “Render All Bypassed Nodes” and “Render All Locked Nodes” options in the render control window.

Usages in other examples

Example name Example for

Subtopics

Clear

  • 3D Texture Generator
    This output operator is used to drive the image3d program which generates 3D texture maps.
  • Alfred
    Alfred is a program shipped out with Pixar’s distribution of RenderMan.
  • Archive Generator
    Generates disk-based archives which can be used by either mantra or RIB renderers.
  • Batch
    Renders the input ROP in a single batch job.
  • 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.
  • Filmbox FBX
    Exports entire scenes to FBX files.
  • 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.
  • 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.
  • Merge
    Merges several render dependencies into one.
  • Net Barrier
    Blocks the ROP network until synhcronization occurs.
  • Null
    Does nothing.
  • Object Scene
    The Object Scene operator allows the creation of many different types of renderings.
  • RenderMan
    Renders the scene using Pixar’s RenderMan renderer.
  • 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.
  • Torque
    Exports the scene to the Torque DTS or DSQ format.
  • Wedge
    Re-renders the same ROP multiple times with different settings
  • Wren
    This output operator is used to drive the Wren rendering program.
  • mental ray
    Renders the scene using the mental ray renderer from mental images.