Houdini 20.0 Nodes Geometry nodes

Topo Landmark geometry node

A state interface to establish correspondence from points on one surface to points on another surface.

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Overview

This Operation is used to create a set of corresponding point pairs. The resulting outputs may be used directly by Topo Transfer as landmark constraints as well as in other SOP networks. For ease of manipulation in downsteam SOP networks the corresponding point pairs are separated into two outputs with a common string attribute to identify the associations.

Creating landmark data in the view state

To...Do this

Generate new landmarks

  1. With the Topo Landmark node selected, click the Handles tool (to the left of the viewer), or move the mouse over the viewer and press Enter.

  2. Click LMB to place the template landmarks on the template geometry.

  3. Press G to switch to the target view.

  4. Position the yellow highlight point to mark a corresponding location on the target geometry.

  5. Press ⎋ Esc to exit the view state.

Create landmarks from initial template point data

  1. Supply some point data to the third input of Topo Landmark.

  2. With the Topo Landmark node selected, click the Handles tool (to the left of the viewer), or move the mouse over the viewer and press Enter.

  3. Set the view state Show option to Target.

  4. Position the yellow highlight point to mark a corresponding location on the target geometry for each template point.

  5. Press ⎋ Esc to exit the view state.

Create landmark correspondence between given template and target point data

  1. Supply some template point data to the third input of Topo Landmark.

  2. Supply some target point data to the fourth input of Topo Landmark.

  3. With the Topo Landmark node selected, click the Handles tool (to the left of the viewer), or move the mouse over the viewer and press Enter.

  4. Set the view state Show option to Template.

  5. Set the view state Mode option to Match.

  6. Select some of the orange template points. Selected template points will turn yellow.

  7. Set the view state Show option to Target.

  8. Select the corresponding purple target point that corresponds to the highlighted template point.

  9. Press ⎋ Esc to exit the view state.

To delete landmarks

  1. Press ⌃ Ctrl + LMB with the mouse hovering over the landmark to delete. NOTE:

    Only landmarks relevent to the current Mode may be deleted.

To supply the Topo Landmark output as landmarks for the Topo Transfer node.

  1. Connect the first output on the Topo Landmark node to the third input on the Topo Transfer node.

  2. Connect the second output on the Topo Landmark node to the fourth input on the Topo Transfer node.

  3. On the Topo Transfer node, toggle on the “Use Landmark Attribute” and specify the attribute that contains the label information.

Tip

For more information about using Topo Landmark with Topo Transfer, see the help page for Topo Transfer.

Landmark toolbar

When in the Topo Landmark view state, a toolbar appears across the top of the viewport. This toolbar contains the controls that allow you to create and edit landmarks.

Mode

Switches between different interactive modes. The options include:

Edit

Allows creating and editing of landmark pairs.

Match

In this mode, landmarks correspondences are established when unstructured template and target points are provided as optional inputs.

Unmatch

This mode allows landmark pairs to be unbound.

Display Landmarks

Controls which types of landmarks to display.

All

Displays the landmarks relevent to all modes.

Selectable

Displays only the landmarks relevent to the current mode.

Label Features

Controls how landmarks labels should be displayed.

Off

No labels are displayed.

On

Displays the label for each landmark pair.

Index

Displays only an index number as the label.

Prefix Label

A string field where the label prefix can be specified.

Show

Switches which landmark guide mesh—template or target—is shown in the viewport.

You can also use the hotkey G to toggle between displaying the template or target guide meshes.

Template

Displays the template landmark guide mesh in the viewport.

Target

Displays the target landmark guide mesh in the viewport.

Show Template Silhouette

When on, displays a transparent version of the template landmark guide mesh when you are viewing the target landmark guide mesh.

Show Geometry Colors

When on, displays either the geometry colors or texture data on the template and target guide mesh. This feature is useful when placing landmarks relative to annotations in the scan data.

Reset Edits

Discards all landmarking done in the view state, and reinitializes the view state from the node input data.

Parameters

Landmark Attribute

The name given to the string attribute on the outputs that will contain the labels.

Label Prefix

A string prefix used before each identification number in the label names.

Inputs

Template Geometry

The template reference geometry on which template points are located.

Tip

  • When used with Topo Transfer, the template geometry used here does not need to be the same as the template geometry used in the Topo Transfer node.

Target geometry

The target reference geometry on which the corresponding target points are located.

Tip

  • When used with Topo Transfer, the target geometry used here does not need to be the same as the target geometry used in the Topo Transfer node.

Template Points

Optional template points to be used when editing the set of correspondence pairs.

Note

The template points may be either labeled or unlabeled.

Target Points

Optional target points to be used when editing the set of correspondence pairs.

Note

The target points may be either labeled or unlabeled.

Examples

TopoLandmarkBasic Example for Topo Landmark geometry node

This example demonstrates how to use the Topo Landmark node with some example scan data and Topo Transfer.

See also

Geometry nodes