In Houdini you can select objects or components and then choose a shelf item or command to apply to the selection, or you can choose a shelf item and the tool will prompt you for the type of selection it needs.

The selection mode buttons and the Select tool are at the top of the toolbox to the left of the 3D view.

See also using handles.

These options are only in the toolbar at the geometry level.

These options are only in the toolbar at the geometry level.

These options are only in the toolbar when selecting objects.

Right-click the Select tool in the toolbox to the left of the viewer to get a menu of general selection options. Some of these options are duplicated in the operation toolbar when the Select tool is active.

The selection mode controls what type of objects/components you are selecting:

Right-click the button to get a menu of object selection options. The object type masks can be if, for example, if you're working with a control nulls for a character and want to prevent accidentally picking lights or cameras in the scene.

When secure selection is on, when you're using a tool other than the selection tool (for example, the Handles tool to interact with the handles of the current node), you cannot change the current selection. You need to switch to the Select tool (hold S) to select components.

This can be useful to prevent accidentally changing the selection when you meant to click a handle. However, it can make it hard to work smoothly in interactive tools like Edit, and it can take time to train yourself to hold a key to select.

To select face loops, hold A and click the first face and the adjacent face in the direction to create the loop.

You can use the flood filling feature to select islands of unselected geometry, or deselect islands of selected geometry.

Hold h and click to flood fill from the component under the mouse. You can also hold ⇧ Shift and/or ⌃ Ctrl to add, remove, or toggle the selection.

Groups are named collections of components (faces, edges, or points). When selecting in the viewport, you can use the group menu icon to select a group instead of/in addition to selecting individual components.

• When selecting components, the operations toolbar across the top of the viewport should have selection-related buttons. Click the Show Group List icon to show or hide the group list in the viewport.

  Even when not selecting, you can click the Show Group List icon in the view toolbar (on the right side of the viewport) to show the group list for visualizing groups.

• You can resize the group list by dragging the sides or corner.

• In the group list, click the Show Group Colors to switch coloring components according to their groups on or off.

• Click a name in the group list to select the components in the group. You can also shift-click the name to add to the current selection and control-click to remove from the current selection.

• Use the items in the gear menu to change or filter the display of group names.

• To select/visualize “islands” of disconnected geometry instead of groups, open the gear menu and choose “3D Connectivity”. To select from disconnected UV pieces, choose “UV Connectivity”. To select from disconnected or unshared edge geometry, choose “Edge Cut Connectivity”. To go back to selecting groups instead of by connectivity, choose “All Groups”.

• To select/visualize areas where a certain attribute has the same value, open the gear menu and choose an attribute name from the Attribute sub-menu.

  Path-like string attribute values are displayed as a hierarchy. Floating-point attributes are broken into 1-unit sized ranges.

• Even when selecting on component type, you can use the gear menu to choose a different component type instead of Match selection type. For example, if you are selecting faces, you can choose Points to work with point groups and point attributes. When you click a point group, Houdini will convert the point group to a face selection.

You can create a linear selection pattern and expand it in various directions to consistently repeat a selection over the geometry.

The base pattern can be defined from the currently selected components. When you press ⇧ Shift + P to set a pattern, the path along the oldest to the most recently selected component forms the base pattern. The last component is considered to be the start of the next iteration of the pattern.

You can expand all components in the selection pattern in 4 directions: forward, backward, left, and right. There are various options for expansion. You can:

• expand each component to just the next component in a direction

• expand each component as much as possible in a direction until you hit a boundary or reach a component that is already in the pattern

• expand to the component currently under the mouse from the closest component in the pattern

There are four types of patterns that can be defined: primitive, point, edge loop, and edge ring.

When you use a tool on the shelf, it operates on the current selection (or prompts you to select something if nothing is selected). The node remembers which components were selected in its parameters. You can go back and change which components the node operators on.

• Right click the selection type icons (Object, Component, Particles, or Dynamics) to show a menu of subtypes which you can allow to be selected or prevent from being selected.

  This lets you, for example, work with characters and props in your scene without worrying about accidentally selecting lights.

• To make selecting overlapping geometry easier, you can choose Edit ▸ Preferences ▸ Objects and Geometry and turn on Popup menu selection.

  When this option is on, if you click to select and the mouse is over multiple pieces of geometry, Houdini gives a list of choices of what to select.

• If you want “secure selection”, “area select visible geometry only”, or “select entire digital asset” to always be on by default, choose Edit ▸ Preferences ▸ Objects and Geometry and turn on the corresponding checkbox.

• You can turn off highlighting of geometry under the mouse pointer. In the main menus, choose Edit ▸ Preferences ▸ Objects and Geometry and turn off Highlight selected geometry in viewport.