SFM Animation Basics: Motion Editor and Graph Editor Explained

The Three Timeline Modes in Source Filmmaker

The SFM timeline has three modes: the Clip Editor, the Motion Editor and the Graph Editor. You switch between them with the three buttons in the upper-left corner of the timeline. Pressing Tab toggles between the Clip Editor and whichever animation editor you used last.

The Clip Editor is where you scrub playback, blade and retime shots, and manage sound and effects clips. You can select controls in the Animation Set Editor while in the Clip Editor, but you cannot modify them. Valve’s documentation is direct about this: animation changes happen only in the Motion Editor or the Graph Editor.

Every model, camera, light and particle system you add gets an animation set. Whatever controls you select in the Animation Set Editor are what the Motion Editor and Graph Editor will change. If you have not added a character yet, our guide to importing SFM models from the Steam Workshop walks through it.

Feature	Clip Editor	Motion Editor	Graph Editor
Main job	Shots, sound and effects clips	Blending poses over a time selection	Precise keyframes and curve shapes
Can change animation	No	Yes	Yes
How time is chosen	Not applicable	Explicit time selection with falloffs	Implicit, set by where keyframes sit
Undo safety net	Standard undo	Floating modification layer (Enter keeps, Esc discards)	Standard undo
Uses presets	No	Yes, all procedural presets	Some presets only
Marks on the timeline	Shot boundaries	Bookmarks (M), can resample at them	Keyframe markers (M), cannot resample
Best for	Editing the film	Body motion, lip sync, quick blocking, noise	Timing, single-axis fixes, camera moves

How the SFM Motion Editor Works

The Motion Editor lets you adjust and blend animation for one or many controls at once, even across several animation sets. You can pose with the 3D manipulators in the viewport, drag control sliders, or drag preset sliders. Any change applies only to the selected controls and only inside the current time selection.

Valve suggests thinking in three parts: what, how and when. Select what to change, make the change, then decide when it applies by adjusting the time selection.

Time Selection

When you first open the Motion Editor, all of time is selected. The whole panel is green, and a vertical green zig-zag handle sits on each side. These are the infinite time selection handles. Any change you make now affects the entire timeline.

• Hold Shift and drag to select a region of time. The selection turns green.
• Drag an infinite handle inward to limit one side.
• Press Ctrl+A to select all of time again.
• Hold Alt and drag an edge to scale the selection.
• Hold Alt and drag inside the selection to retime it, moving it earlier or later.

Falloffs: the Hold and the Ramps

A time selection with falloffs has three parts: a first falloff, a hold in the middle, and a second falloff. The hold gets your full change. The falloffs blend it in and out, which stops a pose from snapping on and off.

To create a falloff, drag the edge of the selection when the pointer becomes a double-headed arrow, or hold Shift and roll the mouse wheel.

Falloffs come in four curve types. Hover over a falloff and press 1 for linear, 2 for dome, 3 for spike or 4 for bell.

The Floating Modification Layer

When you change something in the Motion Editor, the time selection turns from green to orange. Orange means your edit sits in the floating modification layer: a temporary state where you can still slide the selection, reshape falloffs or try another preset.

Press Enter to apply the layer, or press Esc to throw it away. Saving, selecting something else, or Shift-dragging a new selection also applies it. If an edit seems to leak into frames you never meant to touch, check whether the layer was still orange when you started your next selection.

The drop-down on the left of the Motion Editor toolbar sets how each change is applied:

• Transform: applies the change to all motion in the selection, rotating the motion path too.
• Offset: adds the change on top of the existing motion.
• Overwrite: replaces the motion in the selection with your current pose.

Presets: Smooth, Jitter, Stagger and More

The preset sliders sit on the right of the Animation Set Editor under the Procedural tab. A preset slider springs back after each use, because it blends the selected controls toward the preset.

Preset	What it does	Typical use
Smooth	Flattens peaks and valleys in a curve	Cleaning up jittery puppeteered motion
Jitter	Adds random noise to a curve	Shivers, engine shake, nervous hands
Stagger	Offsets several controls by random amounts, scaled by falloff size	Breaking up fingers or hair that move in sync
Hold	Pulls frames in the falloffs toward the hold	Slow-in, slow-out pauses
Release	Pushes frames in the falloffs away from the hold	Fast-in, fast-out, accelerating motion
Steady	Spreads frames evenly across the selection	Constant speed along a curved path
Playhead	Pulls values toward the value at the playhead	Holding a control still

Stagger, Hold, Release and Steady change timing without changing the motion path. On a 3D path, clustered frame circles mean slow motion and spread-out circles mean fast motion. Ctrl+click a control in the viewport to show its motion path on that control. Valve’s Motion Editor documentation covers the rest of these tools.

Bookmarks and Previewing

Press M in the Motion Editor to drop a bookmark at the playhead. You can drag them. Right-click and choose Resample, then At Bookmarks, to flatten the curves between them into straight lines.

How the SFM Graph Editor Works

The Graph Editor shows animation as curves you edit directly with keyframes. There is no explicit time selection. The keyframes you place define the region you are working on, and the curve between two keys is shaped by their tangent handles.

Channels and Transform Components

Select controls in the Animation Set Editor first. Then, in the Graph Editor’s list, pick the components to show. Under transform you find position on the X, Y and Z axes and rotation on each axis. Showing one channel at a time keeps the graph readable.

Keyframes and Markers

Move the playhead to a frame and press M. SFM adds a keyframe to every visible curve at that frame, plus a small blue marker above the playhead. Moving the control in the viewport also adds keys.

Markers look like Motion Editor bookmarks, but dragging one moves all of its keyframes, and you cannot resample at them.

Tangents and Curve Shape

Rectangle-select a keyframe and two tangent handles appear on either side of it. Rectangle-select a handle and drag with the middle mouse button to bend the curve. A steep curve means fast motion, and a flat curve means slow motion or a hold. Some animators also use a stepped tangent, which holds a value until the next key, while they block out poses.

Exact Values and Offset Mode

The X and Y fields at the top of the Graph Editor take exact values for selected keys. They also take math: +=3 adds 3 to every selected key, while 3 sets the value to exactly 3.

Offset mode, toggled by an icon in the middle of the Graph Editor toolbar, keeps fine detail when you move a section of curve. With it off, the same move flattens the curve between the keys. Valve’s keyframing page shows both results side by side.

Your First SFM Animation, Step by Step

This exercise animates a character raising an arm, using the Motion Editor for the main pose and the Graph Editor for timing. Start with a fresh session and one character in a lit map. If SFM is not set up yet, follow our Source Filmmaker install guide first.

Once the motion reads well, frame it. Our SFM camera tips and SFM lighting guide help the pose read clearly.

Motion Editor vs Graph Editor: When to Use Each

Neither editor is the right one for everything. Most animators use both on the same shot:

• Use the Motion Editor for broad body movement, blocking a shot fast, lip sync and facial work, and applying presets like Jitter or Smooth over a range of frames.
• Use the Graph Editor for exact timing, single-axis corrections, camera moves that must start and stop on a given frame, and checking that curves have no sudden spikes.

Both editors change the same curves, so big Motion Editor passes after careful keyframing can undo your polish. Finish broad passes first.

SFM Animation Keyboard Shortcuts

These shortcuts come from Valve’s SFM documentation. For the full list and custom bindings, open Help, then Keyboard Shortcuts.

Action	Shortcut	Where
Toggle Clip Editor and last animation editor	Tab	Timeline
Play or pause	Spacebar	Timeline
Play only the current shot	Ctrl+Spacebar	Timeline
Step one frame back or forward	Left or Right arrow	Timeline
Select a time region	Shift+drag	Motion Editor
Select all of time	Ctrl+A	Motion Editor
Create a falloff	Shift+mouse wheel	Motion Editor
Falloff type: linear, dome, spike, bell	1, 2, 3, 4	Motion Editor
Apply or discard changes	Enter or Esc	Motion Editor
Preview time without the playhead	Hold Shift and move the mouse	Motion Editor
Add bookmark or keyframe marker	M	Both editors
Move selected keys or handles	Middle mouse drag	Graph Editor
Scale selected keys	Ctrl+right-drag	Graph Editor
Pan the graph	Alt+middle mouse drag	Graph Editor

Common SFM Animation Mistakes

• Trying to animate in the Clip Editor. Controls can be selected there but not changed. Press Tab to jump to an animation editor.
• Forgetting that all of time is selected. A pose made on a fresh Motion Editor view changes the whole timeline, not one frame.
• Leaving the floating layer orange. Starting a new Shift-drag selection applies the old change to the old region.
• Dragging the playhead to preview. Its position affects how a manipulation lands, so use Shift preview or Ctrl+Spacebar.
• Over-smoothing. Apply the Smooth preset in small drags and check the curve.
• Showing every channel at once in the Graph Editor. Overlapping curves hide spikes.
• Using the wrong modification mode. Overwrite deletes motion in the selection, which surprises people who expected Offset.

When the animation is ready, our best SFM render settings guide explains how to export it at full quality.

SFM Motion Editor and Graph Editor FAQs