Houdini 20.5 Nodes Object nodes

Sticky object node

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

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This tool creates an object which takes its transform from the world-space position of a UV point on a polygonal surface. You can then parent another object to the Sticky object to make the object follow the surface.

This is similar to the Rivet tool; however, this tool is more precise since you can attach the sticky anywhere on the surface and you can animate the position as well as the object. For example, you could animate a monkey riding on an elephant’s back while sliding across the surface trying to balance.

The Sticky Object gets its transform from the surface of a polygonal mesh. The mesh must also have texture coordinates that are used to determine the parameterization of the polygons.

Sticky Objects may be parented to other sticky objects. In this case they will parent their 2d UV transformation (both the UV offset and the rotation). If one parents sticky objects, the Fetch World Transform should be turned on.

The Sticky Geometry path determines the object to stick to. To stick objects to sticky geometry, you must parent the geometry you want stuck to the Sticky node.

For example to stick a sphere to a grid, make sure the grid has uv texture attributes, create a Sticky Object, set the Sticky Geometry to the grid, and parent the sphere to the Sticky Object.

Parameters

Sticky

Sticky Geometry

The SOP to stick the geometry to.

Attribute

The attribute name of the texture to use for the polygonal parameterization.

UV

The UV coordinates to evaluate the mesh at.

Rotation

The angle to rotate the local coordinate frame about the surface normal. It will only take effect when Orient to Surface is on. However, any other sticky objects parented to this one will inherit this rotation.

Orient To Surface

Whether the local orientation of the point should be used. The surface normal is used as the Z axis and the texture’s U axis is used as the Y axis.

Fetch World Transform

If this is set, the transform of the Sticky Geometry will be used. If not set, the parent transform of this node will be used.

Wrap in U/V

When not set, u and v values outside the range will be ignored. When it is set, they will be wrapped until they lie within the range.

U/V Range

This is the range of texture space to work within. Geometry whose texture coordinates lie outside this range will be ignored.

Assume UV Coordinates Unchanging

The sticky object builds a cache of the target surface’s texture coordinates. When this is set, the cache is kept even if the target’s geometry changes.

Clear UV Caches

The Sticky Object is conservative about rebuilding the UV information. This will force it to update the UV texture lookups.

Render

Display

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.

Set Wireframe Color

Use the specified wireframe color

Wireframe Color

The display color of the object

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.

Geometry Scale

Uniform scaling about the xyz axes.

Display

Whether to display only the icon, only the axis, or both.

Icon

Displays only the icon geometry.

Axis

Displays only the axis.

Icon and Axis

Displays both the icon and axis.

Control Type

Switches between the type of geometry to display.

Null

Displays null geometry (i.e. cross).

Circles

Displays circle primitives.

Box

Displays box primitive.

Planes

Displays plane primitives.

Null and Circles

Displays null and circle primitives.

Null and Box

Displays null and box primitives.

Null and Planes

Displays null and plane primitives.

Custom

If an input source is specified, this option will display the geometry of the input.

Orientation

Used in conjunction with circle or plane primitives. Determines which circles or planes to display.

All planes

Displays circle or plane primitives on the YZ, ZX and XY planes.

YZ plane

Displays a circle or plane primitive on the YZ plane.

ZX plane

Displays a circle or plane primitive on the ZX plane.

XY plane

Displays a circle or plane primitive on the XY plane.

YZ, ZX planes

Displays circle or plane primitives on the YZ and ZX planes.

YZ, XY planes

Displays circle or plane primitives on the YZ and XY planes.

ZX, XY planes

Displays circle or plane primitives on the ZX and XY planes.

Shaded Mode

Determines whether to display the primitives as shaded objects or as wireframe objects.

off

Displays primitives in wireframe mode.

on

Displays primitives in shaded mode.

Examples

StickyDonut Example for Sticky object node

In this example, a donut is stuck to an animated sticky object on the surface of a grid.

See also

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 …

  • Camera

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

  • Common object parameters

  • 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

  • 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.

  • LOP Import

    Imports transform data from a USD primitive in a LOP node.

  • LOP Import Camera

    Imports a USD camera primitive from a LOP node.

  • Labs Fire Presets

    Quickly generate and render fire simulations using presets for size varying from torch to small to 1m high and low

  • 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.

  • 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.

  • 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.

  • Reference Image

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

  • 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.

  • TOP Network

    The TOP Network operator contains object-level nodes for running tasks.

  • VR Camera

    Camera supporting VR image rendering.

  • Viewport Isolator

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

  • glTF