blender-animation

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---
name: blender-animation
description: Animate objects, cameras, lights, and properties in Blender — keyframes, F-curves, easing (Bezier, Linear, Sine, Bounce, Elastic), shape keys (morph targets / blendshapes / visemes), drivers (Python expressions on properties), NLA actions for reuse and layering. Use whenever the user asks to "animate this", "make it move / rotate / scale over time", "add keyframes", "loop / oscillate", "shape key / morph / blendshape", "visemes for lip sync", or any time-based property change. Make sure to use this skill even if the user does not say "animate" — also covers "spin it slowly", "make it wave", "fade in / out", "pulse", "facial expression".
when_to_use: Any time-based animation, keyframe insertion, F-curve manipulation, shape-key editing, or driver setup in Blender.
allowed-tools: Read Bash mcp__blender__execute_blender_code mcp__blender__get_scene_info mcp__blender__get_object_info
---

# Blender Animation

Animate properties over time. Most animation is just keyframes — the trick is choosing the right interpolation and easing for the motion's character.

## Decision tree

```
What kind of motion?
├── Object movement (translate / rotate / scale)
│   → Keyframe `location` / `rotation_euler` / `scale`
│   → Recipe 1, 2
│
├── Mechanical / constant speed (gears, conveyor belts, scrolling)
│   → Linear interpolation
│   → Recipe 3
│
├── Natural / organic (most things)
│   → Bezier interpolation with auto handles
│   → Recipe 1
│
├── Cartoon / stylized (overshoot, bounce, anticipation)
│   → Bounce / Elastic / Back easing
│   → Recipe 4
│
├── Facial / morph / blendshape
│   → Shape Keys, animate `value` property
│   → Recipe 5
│
├── Mechanical relations (one property = function of another)
│   → Drivers (Python expression)
│   → Recipe 6
│
└── Reusable / layered animations
    → NLA actions
    → Recipe 7
```

## Recipes

### Recipe 1 — Animate object position (Bezier, natural)

```python
import bpy

obj = bpy.data.objects['GEO-target']

scene = bpy.context.scene
scene.frame_start = 1
scene.frame_end = 60
scene.render.fps = 24

# Keyframe 1: at frame 1, at origin
scene.frame_set(1)
obj.location = (0, 0, 0)
obj.keyframe_insert('location', frame=1)

# Keyframe 2: at frame 60, moved to (5, 0, 0)
scene.frame_set(60)
obj.location = (5, 0, 0)
obj.keyframe_insert('location', frame=60)

print(f"animated:{obj.name} 1->60")
```

Default interpolation = Bezier (smooth in/out). To make it linear, see Recipe 3.

### Recipe 2 — Animate rotation (a 360° spin)

```python
import bpy, math

obj = bpy.data.objects['GEO-target']
scene = bpy.context.scene

# Use rotation_euler with a single axis.
# WARNING: animating past 180° on Euler can flip; use multiple keyframes or quaternions for full rotations.

scene.frame_set(1)
obj.rotation_euler = (0, 0, 0)
obj.keyframe_insert('rotation_euler', frame=1)

scene.frame_set(120)
obj.rotation_euler = (0, 0, math.radians(180))   # half-turn
obj.keyframe_insert('rotation_euler', frame=120)

scene.frame_set(240)
obj.rotation_euler = (0, 0, math.radians(360))   # full turn
obj.keyframe_insert('rotation_euler', frame=240)

print(f"rotated:{obj.name} 360 over 240 frames")
```

For perfectly constant spin, set keyframes to Linear interpolation (Recipe 3).

### Recipe 3 — Set keyframes to Linear interpolation

⚠ **Blender 5.x changed the Action API.** Legacy `action.fcurves` was removed in favour of layered Actions: `action.layers[].strips[].channelbags[].fcurves`. Use this compat helper.

```python
import bpy

def get_fcurves_compat(action):
    """Return all fcurves on an Action — works on both legacy (≤4.x) and layered (5.x+) actions."""
    if hasattr(action, 'fcurves'):
        return list(action.fcurves)
    fcurves = []
    for layer in action.layers:
        for strip in layer.strips:
            if hasattr(strip, 'channelbags'):
                for cb in strip.channelbags:
                    fcurves.extend(cb.fcurves)
    return fcurves

obj = bpy.data.objects['GEO-target']