User Guide > Overview > Parameters   

Heads-up Display [HUD] Sliders

To streamline the editing of parameters in the viewer pane, Houdini supports the creation of custom heads-up display [HUD] sliders. These sliders link to parameters found in different parts of a Houdini file and give you access to these parameters without having to navigate the network.

You can also use these custom controls for quickly setting keyframes on your object. When keyframes have been set then the slider handle becomes solid red to indicate the presence of a channel.

Tip: HUD sliders are disabled when you are working with some Houdini tools such as the View tool. If your HUD sliders appear dimmed then use another tool such as the Transfrom tool [object level] or the Select tool [geometry level] to re-enable the HUD sliders.

Topics covered:
Creating Heads-up Display Sliders
Arranging HUD sliders
Editing the Slider Range
Managing HUD sliders


Creating Heads-up Display Sliders

A heads-up display slider can be created either by dragging from the Parameter pane to the Viewer pane or using the Persistent Handle Editor.

Drag-and-Drop - Using this method, you click on either a parameter field or a parameter name in the Parameter pane and drag it to the Viewer pane. When you let go you are asked what past method you want to use. Choose HUD Slider and the sliders will be created.

Sliders created using drag and drop are automatically named using the title hudslider and the parameters path. To give the sliders proper names, select Tools > Persistent Handle Editor..., highlight the HUD slider on the list then edit the name field.

Persistent Handle Editor - Select Tools > Persistent Handle Editor... then click on the Create New button and select HUD slider (hudslider). This adds an empty slider to the list. You can now edit its name and assign a parameter to the value field. To assign the parameter, you can either type the parameter path by hand or use the tree view in the lower left of this window to navigate to the desired parameter and drag it to the value field.


Arranging HUD sliders

Once a HUD has been created, you can arrange how it appears in the viewer pane. Clicking and dragging lets you size and position the HUD while clicking with the RMB on any part of the HUD will take you to some other controls.

Position the HUD - Click-drag on the HUD (not the labels) to move it around the viewer pane.

Size the HUD - Click-drag on the dots at the right edge of the HUD to scale the HUD. This makes it larger on screen but does not change the range of the slider.

Lock the HUD - RMB-click on the HUD and select Lock. This will prevent you from moving or sizing the HUD while still letting you work with the slider. To unlock the HUD you must RMB-click specifically on the slider handle.

Docking the HUD - If you have a single parameter HUD, it can be dragged next to another HUD of the same size and it will be automatically docked. Now you can move and manipulate the two HUD sliders as one. To undock the HUD you can RMB-click on the slider and toggle off the dock option.


Editing the Slider Range

By default most sliders use a parameter range of 0 to 1 although the slider can be dragged beyond these values. If you want to set the range to suit your particular needs then you can RMB-click on the HUD and choose Handle Parameters.... In this window, you can set the range and lock the high and low values. This is a great way of limiting the range of the slide and offer very specific control over a parameter.


Managing HUD sliders

Because HUD sliders are persistent handles by default, they will remain visible even after you deselect the object you are working with. In a complex scene you may want multiple HUD sliders available without having them all up on the screen at the same time. The HUD sliders can be hidden and revealed using the display icons in the viewer pane and using the handle list pane.

Viewer pane - When a persistent HUD slider is visible in the viewer pane, an icon appears in the selector and handle control bar found on the left edge of the viewer pane. These icons let you toggle on and off the display of any persistent handles including HUD sliders.

Handle List pane - Select Pane > Handle List to see this handle management tool. After you have created some HUD sliders they will be listed in the handle list at the bottom of the pane.

Above this is the Handle group area where you can hide and reveal multiple handles and HUD sliders at one time. To create a group, select handles and HUD sliders from the handle list then click on the Add Group button. You can add and remove handles using the icons to the right of the Add Group button. To hide a group, click on the box under the H column in the group list. Click the box under the E column to reveal the handles again.