Sticky object node

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

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.

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.

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

off

Displays primitives in wireframe mode.

on

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.

Object nodes

• Create and attach camera to a crowd agent.

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

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

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

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

• Switches or blends between the transformations of several input objects.

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

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

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

• The DOP Network Object contains a dynamic simulation.

• Environment Lights provide background illumination from outside the scene.

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

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

• Crowd example showing a changing formation setup

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

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

• Merges groom data from multiple objects into one.

• Moves the curves of a groom with animated skin.

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

• Runs a physics simulation on the input guides.

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

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

• Generates hair from a skin geometry and guide curves.

• The Handle Object is an IK tool for manipulating bones.

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

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

• Light Objects cast light on other objects in a scene.

• 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.

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

• Import Acclaim motion capture.

• A male character with motion captured animations.

• A male character with motion captured animations.

• A male character with motion captured animations.

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

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

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

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

• Object nodes represent objects in the scene, such as character parts, geometry objects, lights, cameras, and so on.

• The Path object creates an oriented curve (path)

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

• Pxr AOV Light object for RenderMan RIS.

• Pxr Barn Light Filter object for RenderMan RIS.

• Pxr Blocker Light Filter object for RenderMan RIS.

• Pxr Cookie Light Filter object for RenderMan RIS.

• Pxr Day Light object for RenderMan RIS.

• Pxr Disk Light object for RenderMan RIS.

• Pxr Distant Light object for RenderMan RIS.

• Pxr Dome Light object for RenderMan RIS.

• Pxr Gobo Light Filter object for RenderMan RIS.

• Pxr Mesh Light object for RenderMan RIS.

• Pxr Portal Light object for RenderMan RIS.

• Pxr Ramp Light Filter object for RenderMan RIS.

• Pxr Rectangle Light object for RenderMan RIS.

• Pxr Rod Light Filter object for RenderMan RIS.

• Pxr Sphere Light object for RenderMan RIS.

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

• Crowd example showing a simple ragdoll setup.

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

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

• A simple and efficient animation rig with full controls.

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

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

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

• Crowd example showing a stadium setup

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

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

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

• Crowd example showing a street setup with two agent groups

• Container for objects.

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

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