How to turn on onion skin in Blender 3D: Grease Pencil ghosts, settings and Motion Paths

What onion skinning does

Onion skinning shows faint ghosts of the drawings before and after the current frame. You see where the previous pose was and where the next one goes while you draw the in-between.

In Blender, it belongs to Grease Pencil, the 2D drawing system (the Grease Pencil guide covers the basics). Meshes, armatures and other 3D objects have no onion skin setting in Blender 5.2; the last part of this guide covers the alternatives.

How to turn on onion skin in Blender (Grease Pencil)

Grease Pencil was rewritten for Blender 4.3, and the switches below are in the same places from 4.3 to 5.2.

1. Select the Grease Pencil object, in Object Mode or Draw Mode.
2. In the 3D Viewport header, a second dropdown with the Grease Pencil icon sits just right of the Overlays button. Open it and check Onion Skin. The main Overlays toggle has to be on as well.
3. Open the Properties editor, Object Data tab, Layers panel. Each layer in the tree has four icons, and one of them is Onion Skinning. Leave it on for the layers you want to see as ghosts. Since 4.3, layer groups have the same icon, which switches the whole group.
4. Animate at least two drawings. In Draw Mode, Shift+I inserts a blank keyframe on the active layer; draw, move a few frames forward, insert another one and draw again. The previous drawing now shows as a tinted ghost.

The same dropdown has Active Object Only, added in Blender 4.5: with several Grease Pencil objects in the scene, it limits the ghosts to the active one.

Onion skinning settings

The Onion Skinning panel sits in the same Object Data tab, under Layers. Its settings belong to the Grease Pencil data, so they apply to every layer whose onion skin icon is on.

Mode

• Keyframes counts drawings. With Keyframes Before at 2, you see the two previous drawings, however many frames apart they are. It is the natural choice for frame-by-frame drawing.
• Frames counts scene frames. Frames Before at 6 shows the drawings whose keyframe sits within the six previous frames. A drawing keyed earlier is left out, even if it stays on screen until just before the current frame.
• Selected only shows the keyframes you selected in the Dope Sheet, in its Grease Pencil mode. Use it to compare every drawing against one key pose.

Range, opacity and filter

• Keyframes Before and Keyframes After (named Frames Before and Frames After in Frames mode) accept 0 to 120. At 0, nothing shows on that side. Selected mode has no count.
• Opacity sets how visible the ghosts are.
• Filter by Type limits the ghosts to one keyframe type: Keyframe, Breakdown, Moving Hold, Extreme, Jitter or Generated, or All. Set a key's type in the Dope Sheet with Key > Keyframe Type. The Interpolate tool creates Breakdown keys, so filtering on Keyframe hides the in-betweens it generated.

Colors and display

• Custom Colors: enable the checkbox in this subpanel's header, then pick a Before and an After color. Without it, ghosts take the Before Current Frame and After Current Frame colors of the theme, the same ones Motion Paths use.
• Fade, in the Display subpanel, makes ghosts fainter the further they are from the current frame.
• Show Start Frame shows the first drawing as a ghost when you reach the last frame, which is how you check that a loop closes. The panel grays it out in Frames mode: use it with Keyframes or Selected.

Onion skin not showing? Check these

• Overlays: the main Overlays toggle is off, or Onion Skin is unchecked in the Grease Pencil dropdown.
• The layer: its onion skin icon is off, or the icon of the group that contains it.
• Playback: Blender hides the ghosts while the animation plays. Scrub the timeline or step frame by frame to see them.
• Rendered shading: ghosts are not drawn in Rendered viewport shading. Switch to Solid or Material Preview.
• Nothing to show: a single keyframe, Before and After at 0, or a Filter by Type that matches no key.
• Active Object Only is checked and another object is active.
• One material is missing from the ghosts: in the Material tab, each material in the list has an onion skin icon (Show in Ghosts). Turned off, strokes with that material never appear as ghosts.

Onion skin for 3D objects: Motion Paths

For a 3D object or a rig, the built-in tool is Motion Paths. Instead of ghosting the whole shape, Blender draws the path of a point (an object origin or a bone joint) with a dot on every frame. With the default theme, the part already played is red and the part to come is green.

For an object

1. Select the animated object in Object Mode.
2. Open the Properties editor, Object tab, Motion Paths panel.
3. Choose the Paths Type: Around Frame shows a set number of frames before and after the current one, In Range shows a fixed range.
4. Click Calculate... and confirm the range.

For bones

In Pose Mode, select the bones, then Pose > Motion Paths > Calculate. The same settings are in the Armature tab of the Properties editor, Motion Paths panel. In the Calculate dialog, Bake Location sets whether the path follows the heads or the tails of the bones.

Paths update by themselves when you edit keyframes. If you change the Calculation Range, click Update Path. In the Display subpanel, Frame Numbers labels each dot and Keyframes highlights keyed frames. If no path appears, check that Motion Paths is enabled in the Viewport Overlays.

An onion skin add-on for meshes

For true ghosts of a mesh, B Onion Skin is a free third-party add-on listed on extensions.blender.org. It is not made by the Blender Foundation; at the time of writing, version 1.1.0 lists Blender 5.2 LTS and newer. Install it from Edit > Preferences > Get Extensions: search for its name and click Install. Its panel is in the 3D Viewport Sidebar (N), Onion Skin tab. Select the mesh or the armature, click Add Selected, then enable the checkbox in the panel header.

What onion skinning helps you fix

• Spacing: ghosts close together read as slow movement, ghosts far apart as fast movement. A slow out shows as gaps that widen after a pose, a slow in as gaps that shrink before the next one. With 3D objects, the distance between Motion Path dots gives the same information.
• Arcs: line the ghosts up along a curve, and a drawing that falls off it stands out. For a rig, Motion Paths on the head or a hand do the same job, as in the walk cycle guide.
• Rubber hose limbs: with the previous pose visible, you can keep the length and curve of a boneless arm consistent from drawing to drawing. See rubber hose animation in Blender.
• Smear frames: a smear stretches a shape between two positions, and the ghosts show exactly where those positions are. See the smear frames guide.
• Loops: Show Start Frame puts the first drawing over the last one, so the cycle joins without a pop.

The Blender animation guide covers keyframes, the Timeline and the Graph Editor.