Houdini 17.5 Nodes Object nodes

Subnet object node

Container for objects.

On this page

You can use subnets to simplify complex networks by creating a hierarchy. You can put multiple objects inside a subnet and use it like an object. You can also nest subnets inside subnets.

See more about subnets and other methods for organizing scenes.



Transform Order

The left menu chooses the order in which transforms are applied (for example, scale, then rotate, then translate). This can change the position and orientation of the object, in the same way that going a block and turning east takes you to a different place than turning east and then going a block.

The right menu chooses the order in which to rotate around the X, Y, and Z axes. Certain orders can make character joint transforms easier to use, depending on the character.


Translation along XYZ axes.


Degrees rotation about XYZ axes.


Non-uniform scaling about XYZ axes.


Local origin of the object. See also setting the pivot point .

Uniform Scale

Scale the object uniformly along all three axes.

Modify Pre-Transform

This menu contains options for manipulating the pre-transform values. The pre-transform is an internal transform that is applied prior to the regular transform parameters. This allows you to change the frame of reference for the translate, rotate, scale parameter values below without changing the overall transform.

Clean Transform

This reverts the translate, rotate, scale parameters to their default values while maintaining the same overall transform.

Clean Translates

This sets the translate parameter to (0, 0, 0) while maintaining the same overall transform.

Clean Rotates

This sets the rotate parameter to (0, 0, 0) while maintaining the same overall transform.

Clean Scales

This sets the scale parameter to (1, 1, 1) while maintaining the same overall transform.

Extract Pre-transform

This removes the pre-transform by setting the translate, rotate, and scale parameters in order to maintain the same overall transform. Note that if there were shears in the pre-transform, it can not be completely removed.

Reset Pre-transform

This completely removes the pre-transform without changing any parameters. This will change the overall transform of the object if there are any non-default values in the translate, rotate, and scale parameters.

Keep Position When Parenting

When the object is re-parented, maintain its current world position by changing the object’s transform parameters.

Child Compensation

When the object is being transformed, maintain the current world transforms of its children by changing their transform parameters.

Enable Constraints

Enable Constraints Network on the object.


Path to a CHOP Constraints Network. See also creating constraints.


You can you use the Constraints drop down button to activate one of the Constraints Shelf Tool. If you do so, the first pick session is filled automatically by nodes selected in the parameter panel.


Lookat and Follow Path parameters on object nodes are deprecated in favor of Look At and Follow Path constraints. The parameters are only hidden for now and you can set their visibility if you do edit the node’s parameter interface.


Input Labels

Labels for the four inputs to the subnetwork. These labels appear when you press on the input connections. This is useful to document the purpose of each input.


Whether or not this object is displayed in the viewport and rendered. Turn on the checkbox to have Houdini use this parameter, then set the value to 0 to hide the object in the viewport and not render it, or 1 to show and render the object. If the checkbox is off, Houdini ignores the value.

Output Transform

The object inside the subnet from which to get the subnet’s output transform, or one of the inputs to use as the parent.


The local transform of the subnet is currently always the transform computed from its transform parameters. So it may be inconsistent with its world transform when this is set to a child object.

Visible children

Space separated list of objects inside the subnet to display. Use * to make all objects visible (the default). You can use wildcards and bundle references to specify objects.

This parameter lets you:

  • Quickly filter the visible objects based on an existing naming convention, for example *_proxy.

  • Control visibility of objects inside a locked digital asset where the display flags are not available.

Otherwise, in a normal subnet you can simply go into the subnet and set the display flag on objects.

Viewport Selecting Enabled

Object is capable of being picked in the viewport.

Select Script

Script to run when the object is picked in the viewport. See select scripts .

Cache Object Transform

Caches object transforms once Houdini calculates them. This is especially useful for objects whose world space position is expensive to calculate (such as Sticky objects), and objects at the end of long parenting chains (such as Bones). This option is turned on by default for Sticky and Bone objects.

See the OBJ Caching section of the Houdini Preferences window for how to control the size of the object transform cache.


The following examples include this node.

FractureExamples Example for Voronoi Fracture Solver dynamics node

This example actually includes eight examples of ways that you can use voronoi fracturing in Houdini. In particular, it shows how you can use the Voronoi Fracture Solver and the Voronoi Fracture Configure Object nodes in your fracture simulations. Turn on the display flags for these examples one at a time to play the animation and dive down into each example to examine the setup.

FirePit Example for Material shader node


No geometry is animated in this file. All animation is achieved by animating the textures

Flames are grids so that UV textures can easily be applied, they are then warped around a metaball using a magnet SOP. The flames are then assigned to either a yellow or blue Flames texture. The Flames' opacity mask wrap is set to Decal to prevent the texture from repeating and showing a single pixel ring at the top of the flame geometry. I'm also using a mask file named flameOpacMap.jpg to enhance the flames' shape at the top. The noise offset has been animated over $T with an greater emphasis on the Y axis so that the flames look like they are rising. This is the same reason the Noise jitter is larger for the Y axis as well.

The coals are spheres that have been copy stamped onto a deformed grid. Using Attribute Create surface nodes I am able to override and copy stamp the lava texture’s parameters at the SOP level so that local variables, such as $BBY, can be used to animate the texture. This way the texture’s crust and its crust values can be used only to form the tops of the coals. This reserves the lava aspect of the texture to be used on the bottoms of the coals. The lava intensity (Kd attribute) is then stamped and animated to create the look of embers on the bottom of coals glowing.

AgentRelationshipBasic Example for Agent Relationship geometry node

This example demonstrates how to create a simple parent-child agent setup.

FurBallWorkflow Example for Fur geometry node

This example demonstrates how the Fur SOP and Mantra Fur Procedural can be applied to an animated skin geometry. CVEX shaders are used to apply a custom look to the hairs based upon attributes assigned to the geometry.

example_top_renderifd Example for Render IFD TOP node

This example demonstrates how to render ifd files using the renderifd node.

Object nodes

  • Agent Cam

    Create and attach camera to a crowd agent.

  • Alembic Archive

    Loads the objects from an Alembic scene archive (.abc) file into the object level.

  • Alembic Xform

    Loads only the transform from an object or objects in an Alembic scene archive (.abc).

  • Ambient Light

    Adds a constant level of light to every surface in the scene (or in the light’s mask), coming from no specific direction.

  • Auto Bone Chain Interface

    The Auto Bone Chain Interface is created by the IK from Objects and IK from Bones tools on the Rigging shelf.

  • Blend

    Switches or blends between the transformations of several input objects.

  • Blend Sticky

    Computes its transform by blending between the transforms of two or more sticky objects, allowing you to blend a position across a polygonal surface.

  • Bone

    The Bone Object is used to create hierarchies of limb-like objects that form part of a hierarchy …

  • COP2 Plane

    Container for the Compositing operators (COP2) that define a picture.

  • Camera

    You can view your scene through a camera, and render from its point of view.

  • Dop Network

    The DOP Network Object contains a dynamic simulation.

  • Environment Light

    Environment Lights provide background illumination from outside the scene.

  • Extract Transform

    The Extract Transform Object gets its transform by comparing the points of two pieces of geometry.

  • Fetch

    The Fetch Object gets its transform by copying the transform of another object.

  • Formation Crowd Example

    Crowd example showing a changing formation setup

  • Franken Muscle

    Creates a custom muscle by combining any number of geometry objects, muscle rigs, and muscle pins.

  • Fuzzy Logic Obstacle Avoidance Example

  • Fuzzy Logic State Transition Example

  • Geometry

    Container for the geometry operators (SOPs) that define a modeled object.

  • Groom Merge

    Merges groom data from multiple objects into one.

  • Guide Deform

    Moves the curves of a groom with animated skin.

  • Guide Groom

    Generates guide curves from a skin geometry and does further processing on these using an editable SOP network contained within the node.

  • Guide Simulate

    Runs a physics simulation on the input guides.

  • Hair Card Generate

    Converts dense hair curves to a polygon card, keeping the style and shape of the groom.

  • Hair Card Texture Example

    An example of how to create a texture for hair cards.

  • Hair Generate

    Generates hair from a skin geometry and guide curves.

  • Handle

    The Handle Object is an IK tool for manipulating bones.

  • Indirect Light

    Indirect lights produce illumination that has reflected from other objects in the scene.

  • Instance

    Instance Objects can instance other geometry, light, or even subnetworks of objects.

  • Light

    Light Objects cast light on other objects in a scene.

  • Light template

    A very limited light object without any built-in render properties. Use this only if you want to build completely custom light with your choice of properties.

  • Microphone

    The Microphone object specifies a listening point for the SpatialAudio CHOP.

  • Mocap Acclaim

    Import Acclaim motion capture.

  • Mocap Biped 1

    A male character with motion captured animations.

  • Mocap Biped 2

    A male character with motion captured animations.

  • Mocap Biped 3

    A male character with motion captured animations.

  • Muscle

    The Muscle object is a versatile tool that can be used when rigging characters and creatures with musculature.

  • Muscle Pin

    Creates a simple rigging component for attaching regions of a Franken Muscle to your character rig.

  • Muscle Rig

    Creates the internal components of a muscle (the rig), by stroking a curve onto a skin object.

  • Null

    Serves as a place-holder in the scene, usually for parenting. this object does not render.

  • Path

    The Path object creates an oriented curve (path)

  • PathCV

    The PathCV object creates control vertices used by the Path object.

  • Pxr AOV Light

    Pxr AOV Light object for RenderMan RIS.

  • Pxr Barn Light Filter

    Pxr Barn Light Filter object for RenderMan RIS.

  • Pxr Blocker Light Filter

    Pxr Blocker Light Filter object for RenderMan RIS.

  • Pxr Cookie Light Filter

    Pxr Cookie Light Filter object for RenderMan RIS.

  • Pxr Day Light

    Pxr Day Light object for RenderMan RIS.

  • Pxr Disk Light

    Pxr Disk Light object for RenderMan RIS.

  • Pxr Distant Light

    Pxr Distant Light object for RenderMan RIS.

  • Pxr Dome Light

    Pxr Dome Light object for RenderMan RIS.

  • Pxr Gobo Light Filter

    Pxr Gobo Light Filter object for RenderMan RIS.

  • Pxr Mesh Light

    Pxr Mesh Light object for RenderMan RIS.

  • Pxr Portal Light

    Pxr Portal Light object for RenderMan RIS.

  • Pxr Ramp Light Filter

    Pxr Ramp Light Filter object for RenderMan RIS.

  • Pxr Rectangle Light

    Pxr Rectangle Light object for RenderMan RIS.

  • Pxr Rod Light Filter

    Pxr Rod Light Filter object for RenderMan RIS.

  • Pxr Sphere Light

    Pxr Sphere Light object for RenderMan RIS.

  • Python Script

    The Python Script object is a container for the geometry operators (SOPs) that define a modeled object.

  • Ragdoll Run Example

    Crowd example showing a simple ragdoll setup.

  • Rivet

    Creates a rivet on an objects surface, usually for parenting.

  • Simple Biped

    A simple and efficient animation rig with full controls.

  • Simple Female

    A simple and efficient female character animation rig with full controls.

  • Simple Male

    A simple and efficient male character animation rig with full controls.

  • Sound

    The Sound object defines a sound emission point for the Spatial Audio chop.

  • Stadium Crowds Example

    Crowd example showing a stadium setup

  • Stereo Camera Rig

    Provides parameters to manipulate the interaxial lens distance as well as the zero parallax setting plane in the scene.

  • Stereo Camera Template

    Serves as a basis for constructing a more functional stereo camera rig as a digital asset.

  • Sticky

    Creates a sticky object based on the UV’s of a surface, usually for parenting.

  • Street Crowd Example

    Crowd example showing a street setup with two agent groups

  • Subnet

    Container for objects.

  • Switcher

    Acts as a camera but switches between the views from other cameras.

  • Tissue Solver

    Collects muscles, anatomical bone models, and skin objects and places them into a single dynamics simulation.

  • Toon Character

    A ready-to-animate Toon Character.

  • Top Network

    The TOP Network Object contains nodes to running tasks

  • VR Camera

    Camera supporting VR image rendering.

  • Viewport Isolator

    A Python Script HDA providing per viewport isolation controls from selection.

  • glTF

  • pxr Int Mult Light Filter

    pxr Int Mult Light Filter object for RenderMan RIS.