Houdini 20.0 Nodes Object nodes

Extract Transform object node

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

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Since 11.0

The Extract Transform Object gets its transform by looking at the points of two SOP geometries. The difference of these point clouds is projected into a rigid transform consisting of a rotation and translation, and this then becomes the transform of this object.

This extraction is very useful when you have baked geometry files which represent rigid motion and want to recover that rigid motion at object level.

The resulting transform may contain reflections that will invert normals if the object is close to planar. To resolve this, you can add extra marker points to the two objects, such as an Attribute Wrangle set to addpoint(geoself(), @P + 0.1*@N); to prevent extraction of an inverted transform.

Parameters

Source Geometry

Path to the SOP geometry to use as the rest reference geometry.

Destination Geometry

Path to the SOP geometry to use as the goal geometry. The transform will transform the source geometry into the destination geometry.

Extract Translate

Whether to use the motion of the point cloud.

Extract Rotate

Whether to use the rotation of the point cloud. This is always measured about the average of the points in the point cloud.

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.

Enable Constraints

Enable Constraints Network on the object.

Constraints

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

Tip

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.

Note

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.

Examples

extracttransform Example for Extract Transform object node

This example shows how to parent geometry to a moving piece of geometry that is defined by a prebaked .bgeo sequence.

Object nodes

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  • Alembic Xform

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  • Ambient Light

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  • Auto Bone Chain Interface

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  • Blend

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  • 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

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  • Common object parameters

  • Dop Network

    The DOP Network Object contains a dynamic simulation.

  • Environment Light

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  • 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

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

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    Merges groom data from multiple objects into one.

  • Guide Deform

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  • 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

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  • Hair Card Texture Example

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

  • Hair Generate

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  • Handle

    The Handle Object is an IK tool for manipulating bones.

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  • 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

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  • 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

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  • 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.

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  • Simple Biped

    A simple and efficient animation rig with full controls.

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  • Sound

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  • Stadium Crowds Example

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  • Stereo Camera Template

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  • Sticky

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

  • Street Crowd Example

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  • Subnet

    Container for objects.

  • Switcher

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  • TOP Network

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  • VR Camera

    Camera supporting VR image rendering.

  • Viewport Isolator

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

  • glTF