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Overview

The playbar controls the current time displayed in the viewer, playback of animation and simulation, and the playback range. The playbar also displays keys for the parameters in the Channel List, and you can edit keys directly on the timeline. The round keyframe button changes color based on the keys at the current time, and clicking it adds keys at the current time.

Playback controls, first row

First frame

Moves the playhead to the start of the current frame range.

Play Backwards

Starts playing the animation in the current frame range backward.

Stop playback

Stops playing the animation.

Play forward

Starts playing the animation in the current frame range. The button turns into a pause button while playback is active. Pressing it again stops the playback.

Last frame

Moves the playhead to the end in the current frame range.

Current Frame

Displays the current frame number. You can use the ladder using the drag or type a frame number.

Previous frame

Moves the playhead to the previous frame. At the start of the current frame range, this can be made to wrap to the end by enabling the Loop Backwards option on the Play looping button.

Next frame

Moves the playhead to the next frame. At the end of the current frame range this wraps to the start.

Playback controls, second row

Global Animation Options

Opens the Global Animation Options window with settings for animation, including the total number of frames are in the current scene.

Open audio panel

Opens a window with settings for audio playback.

Play looping

This pop-up menu lets you choose how/whether playback loops when it reaches the end of the frame range. You can choose Loop (repeat), Play once (stop at the end), or Zig-Zag (repeat forward then backward). There is also an option to Loop Backward.

Real time playback

Toggles real-time mode. When this is on, Houdini will drop frames to try to maintain the correct FPS. When this is off, Houdini will display every frame even if this is slower than real-time.

Click to open the Global Animation Options window to choose realtime playback options.

Previous keyframe

Moves the playhead to the previous keyframe for the selected object.

Go to next keyframe

Moves the playhead to the next keyframe for the selected object.

Timeline

The timeline is a graphical representation of the current frame range. The current frame is highlighted with a black box with a down arrow indicator. Keys on the Channel List appear as marks on the timeline. You can edit keyframes directly on the timeline using the and draw rectangle selection selections using Shift+LMB.

See how key marks are color coded on the timeline.

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Go to a specific frame

  • Click or drag in the timeline to set the current frame.

  • Type an exact frame number in the current frame field.

  • Use the and buttons next to the current frame field to increase or decrease the current frame.

  • Click ⇧ Shift + in the timeline to flip between the last two frames viewed.

Tip

A thin vertical line is displayed under the mouse cursor to indicate the frame number.

Time Range

The time range controls are under the timeline. You can change the global frame range, and the frame range. You can also resize and move the frame range using a scrollbar.

The inner edit boxes surrounding the scrollbar are the start and end frame. The outer edit boxes ,with a lighter background color, are the global start and global end frame.

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Set the frame range

There are two frame ranges: the overall frame range is set in the Global Animation Options. Within this range, you can use controls on the timeline to it to show and playback a subset of the total frame range. This lets you concentrate on subsections of the total animation.

Set the total number of frames

  1. Click to open the Global Animation Options window.

  2. Change the End option and click Apply.

Editing keys on the timeline

You can edit keys directly on the timeline without opening the animation editor when it’s more convenient. Editing keys on the timeline is very similar to editing in the dopesheet.

The timeline only shows key markers for the channels in the Channel List.

To...Do this

Move a single key along the timeline

click a green rectangle and drag to move keyframes in the timeline.

You can on an area without a key to make a quick one frame range selection. Once you have a selection, you have access to all the operations of a range selection.

Move keys along the timeline using a range selection

Hold ⇧ Shift and click or drag to edit keyframes in the timeline. Holding ⇧ Shift puts you in "editing" mode instead of moving the playhead along the timeline.

(You can keep holding ⇧ Shift and select multiple ranges at the same time.)

⇧ Shift +

  • Drag on the timeline to select a range.

  • Drag the selection to move it.

  • Drag the solid squares at either end to resize the selection.

  • Drag a range to move the selected keys.

  • Drag the solid squares at either end of the selection to scale the selected keys.

⇧ Shift +

Clear the timeline selection.

Right-click the timeline to access a menu of commands for editing the selected keys. For example, you can delete keys on the timeline by selecting them, right-clicking and choosing Delete keys.

Hold channels

This is a quick way to copy the values of the channels from one frame to another, such as when you want an object to ping-pong back and forth between two positions.

  1. Go to the frame you want to copy the values from.

  2. Middle-drag the current frame marker to the frame you want to copy to. The values of the scoped channel appear not to change as you drag, but you will see an orange triangle and an orange key.

  3. Press K to key the held values at the current frame, or click another frame on the timeline to cancel the hold.

Copy and paste keys

  1. Use ⇧ Shift + to select a range of keys, then right-click and choose Cut or Copy.

  2. Use ⇧ Shift + to select the range of frames you want to paste into.

  3. Right-click in the timeline and choose one of the following…

Paste

Copies keys from the clipboard into the current selection.

Replace

Replaces the current selection with the contents of the clipboard.

Stretch/Paste

Stretches the contents of the clipboard to fill the selection, if the new selection is a different size than when you cut/copied.

Paste as cycle

Repeats the contents of the clipboard to fill the selection, if the new selection is longer than when you cut/copied.

Paste as cycle with offset

Repeats the contents of the clipboard with offsets to fill the selection, if the new selection is longer than when you cut/copied.

Paste keys visually

The visual paste options on the context menu let you interactively position the paste location with the mouse, instead of selecting it first and then pasting. First, cut or copy a set of keys. If you want to visually paste a repeat or cycle, select a longer range of frames than you have keys – the range will be filled with repeats/cycles when you paste.

Right-click in the timeline and choose one of the following…

Visual replace

Lets you interactively position the clipboard data on the dopesheet, replacing the current contents.

Visual stretch/paste

Lets you interactively position the clipboard data on the dopesheet. Stretches the clipboard data to match the current size of the selection.

Visual paste as cycle

Lets you interactively position the clipboard data on the dopesheet. Repeats the clipboard data to match the current size of the selection.

Visual paste as cycle with offset

Lets you interactively position the clipboard data on the dopesheet. Repeats the clipboard data with offsets to match the current size of the selection.

Use the mouse to position the pasted keys on the timeline. Shift-click to paste the keys, or press ⎋ Esc to cancel pasting.

Keyframing Controls

The right side of the playbar focuses on keyframing controls. It features a large keyframe button with a drop-down menu button for quick access to keyframing preferences, a Channel List button showing an overview of the channel list, a channel list refresh button, a quick access button for the animation editor, and combo box for the Global Set Key preference.

Pressing the keyframe button with channels in the channel list will set a keyframe at the current time on all the channels or on the selected channels based on the Global_Set_Key preference. It does the same as pressing the K key.

Keyframe Button Colors

The keyframe button’s color change if the parameters in the channel list have a keyframe at the current frame.

Keyframing Modes

The keyframe button also shows the state of some Animation Preferences by using a different icon. You can quicky change Auto-Key and Auto-Commit animation preferences by clicking on the drop-down menu button next to the keyframe button. By default, Auto-Key is off and Auto-Commit is on. In this state, the keyframe button is rendered without any decoration. If you turn Auto-Commit off, the keyframe button will be rendered with a little check mark icon. This tells you need to always commit your changes before moving the timeline. In that state, the keyframe button will turn orange really often. If you turn Auto-Key on, the keyframe button is rendered with the label AUTO on it. In that mode, Auto-Commit has no effect, since Auto-Key adds as soon as you change a parameter value.

Channel List Button

Clicking on the channel list button opens a small Channel List popup window right on top of the playbar. The button is wide to display information about the content of the channel list. It displays the numbers channels with keys at the current frame, the number of selected channels, the total number of channels and also if channel filtering it active. The Channel List Button also shows the state of the Auto-Update Channel List and Keep Channel List Selection preferences. A lock icon is displayed when the Auto-Update Channel List is off. A select icon with an orange background is displayed when Keep Channel List Selection is on. A lock icon with an orange background is displayed when Auto-Update Channel List is off and Keep Channel List Selection is on.

Tip

The button supports drag and drop. You can do a drag and drop from a parameter label on it to add channels to the Channel List. You can also drag from the Channel List button onto a Python Shell pane to get the list of hou.Parm in a python array.

Channel List Refresh

Clicking on the channel list refresh button forces a refresh of the Channel List from the selected nodes. The button also has a drop down menu to change Auto-Update Channel List, Keep Channel List Selection animation preferences.

Animation Editor

Opens the Animation Editor floating window.

Global Set Key

Controls the behavior of the keyframe button and the K key. You can choose from Key Pending, Key All Channels, Key Selected.

Animation

Getting started

Next steps