Terminal.skills
Skills/blender-animation
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blender-animation

Animate 3D objects and characters in Blender with Python. Use when the user wants to keyframe properties, create armatures and rigs, set up IK/FK chains, animate shape keys for facial animation, edit F-Curves, use the NLA editor to blend actions, add drivers for expression-based animation, or script any animation workflow in Blender.

#blender#animation#rigging#keyframes#armature
terminal-skillsv1.0.0
Works with:claude-codeopenai-codexgemini-clicursor
Source

Usage

$
✓ Installed blender-animation v1.0.0

Getting Started

  1. Install the skill using the command above
  2. Open your AI coding agent (Claude Code, Codex, Gemini CLI, or Cursor)
  3. Reference the skill in your prompt
  4. The AI will use the skill's capabilities automatically

Example Prompts

  • "Create a responsive landing page layout following our brand guidelines"
  • "Review this component for accessibility issues and suggest fixes"

Documentation

Overview

Create and control animations in Blender using Python. Keyframe object and bone transforms, build armatures with IK/FK rigs, animate shape keys for facial motion, edit F-Curves for timing control, layer actions in the NLA editor, and wire up drivers for expression-based automation — all scriptable from the terminal.

Instructions

1. Keyframe object properties

python
import bpy

obj = bpy.data.objects["Cube"]
# Keyframe location at multiple frames
for loc, frame in [((0,0,0), 1), ((5,0,3), 30), ((5,4,0), 60)]:
    obj.location = loc
    obj.keyframe_insert(data_path="location", frame=frame)

# Also works for rotation_euler, scale, single-axis (index=2 for Z), custom props
obj.rotation_euler = (0, 0, 3.14159)
obj.keyframe_insert(data_path="rotation_euler", frame=60)
obj.scale = (2, 2, 2)
obj.keyframe_insert(data_path="scale", frame=60)
obj["intensity"] = 1.0  # custom property
obj.keyframe_insert(data_path='["intensity"]', frame=30)
bpy.context.scene.frame_start, bpy.context.scene.frame_end = 1, 60

2. Control F-Curve interpolation and modifiers

python
import bpy

action = bpy.data.objects["Cube"].animation_data.action
for fcurve in action.fcurves:
    for kp in fcurve.keyframe_points:
        kp.interpolation = 'BEZIER'  # CONSTANT, LINEAR, BEZIER, SINE, EXPO, BOUNCE, ELASTIC
        kp.easing = 'EASE_IN_OUT'   # AUTO, EASE_IN, EASE_OUT, EASE_IN_OUT
    # Cycles modifier to loop the animation
    mod = fcurve.modifiers.new(type='CYCLES')
    mod.mode_before = 'REPEAT'       # NONE, REPEAT, REPEAT_OFFSET, MIRROR
    mod.mode_after = 'REPEAT'

# Add noise to a specific channel
z_curve = action.fcurves.find("location", index=2)  # Z location
if z_curve:
    noise = z_curve.modifiers.new(type='NOISE')
    noise.strength, noise.scale = 0.3, 5.0

3. Create armatures and bones

python
import bpy

arm_data = bpy.data.armatures.new("Rig")
arm_obj = bpy.data.objects.new("Rig", arm_data)
bpy.context.collection.objects.link(arm_obj)
bpy.context.view_layer.objects.active = arm_obj
bpy.ops.object.mode_set(mode='EDIT')
# (name, head, tail, parent_name, connected)
bone_defs = [
    ("Spine",      (0,0,1.0),   (0,0,1.4),   None,       False),
    ("Chest",      (0,0,1.4),   (0,0,1.8),   "Spine",    False),
    ("UpperArm.L", (0.2,0,1.7), (0.5,0,1.4), "Chest",    False),
    ("Forearm.L",  (0.5,0,1.4), (0.8,0,1.1), "UpperArm.L", True),
    ("Thigh.L",    (0.1,0,1.0), (0.1,0,0.5), "Spine",    False),
    ("Shin.L",     (0.1,0,0.5), (0.1,0,0.05),"Thigh.L",  True),
]
for name, head, tail, parent, connected in bone_defs:
    b = arm_data.edit_bones.new(name)
    b.head, b.tail = head, tail
    if parent:
        b.parent = arm_data.edit_bones[parent]
        b.use_connect = connected

bpy.ops.object.mode_set(mode='OBJECT')

4. Set up constraints on bones

python
import bpy

arm_obj = bpy.data.objects["Rig"]
bpy.context.view_layer.objects.active = arm_obj
bpy.ops.object.mode_set(mode='POSE')
# IK — use an empty as target, chain_count limits affected bones
ik = arm_obj.pose.bones["Forearm.L"].constraints.new('IK')
ik.target = bpy.data.objects["IK_Target"]
ik.pole_target = bpy.data.objects["IK_Pole"]
ik.chain_count = 2

# Copy Rotation — mirrors another object's rotation
cr = arm_obj.pose.bones["Chest"].constraints.new('COPY_ROTATION')
cr.target = bpy.data.objects["ChestCtrl"]
# Other types: LIMIT_ROTATION, DAMPED_TRACK, STRETCH_TO, COPY_LOCATION, TRACK_TO

bpy.ops.object.mode_set(mode='OBJECT')

5. Keyframe bone poses

python
import bpy, math

arm_obj = bpy.data.objects["Rig"]
bpy.context.view_layer.objects.active = arm_obj
bpy.ops.object.mode_set(mode='POSE')
if not arm_obj.animation_data:
    arm_obj.animation_data_create()
action = bpy.data.actions.new("WalkCycle")
arm_obj.animation_data.action = action

# Keyframe thigh swing: back → neutral → forward
thigh = arm_obj.pose.bones["Thigh.L"]
for angle, frame in [(-30, 1), (0, 13), (30, 25)]:
    thigh.rotation_euler = (math.radians(angle), 0, 0)
    thigh.keyframe_insert(data_path="rotation_euler", frame=frame)

bpy.ops.object.mode_set(mode='OBJECT')

6. Create and animate shape keys

python
import bpy

obj = bpy.data.objects["Head"]
mesh = obj.data
if not mesh.shape_keys:  # Basis key required first
    obj.shape_key_add(name="Basis", from_mix=False)

smile = obj.shape_key_add(name="Smile", from_mix=False)
for i, vert in enumerate(smile.data):
    if i in [42, 43, 56, 57]:  # mouth corner vertices
        vert.co.z += 0.02

# Animate shape key value (0.0 → 1.0 → 0.0)
sk = mesh.shape_keys.key_blocks["Smile"]
for val, frame in [(0.0, 1), (1.0, 15), (0.0, 30)]:
    sk.value = val
    sk.keyframe_insert(data_path="value", frame=frame)

7. Layer actions with the NLA editor

python
import bpy

arm_obj = bpy.data.objects["Rig"]
if not arm_obj.animation_data:
    arm_obj.animation_data_create()
# Push actions as NLA strips on separate tracks
track1 = arm_obj.animation_data.nla_tracks.new()
track1.name = "Walk"
strip1 = track1.strips.new("Walk", start=1, action=bpy.data.actions["WalkCycle"])
strip1.repeat = 4                    # loop 4 times
strip1.blend_type = 'REPLACE'        # REPLACE, COMBINE, ADD, SUBTRACT, MULTIPLY

track2 = arm_obj.animation_data.nla_tracks.new()
track2.name = "Wave"
strip2 = track2.strips.new("Wave", start=25, action=bpy.data.actions["WaveHand"])
strip2.blend_type = 'COMBINE'        # blend on top of walk
strip2.influence = 0.8               # partial blend

arm_obj.animation_data.action = None  # clear active action so NLA takes over

8. Add drivers for expression-based animation

python
import bpy

driver = bpy.data.objects["Cube"].driver_add("location", 2).driver  # drive Z location
driver.type = 'SCRIPTED'
driver.expression = "sin(frame * 0.1) * 2"
# Add a variable that reads another object's transform
var = driver.variables.new()
var.name = "ctrl"
var.type = 'TRANSFORMS'
var.targets[0].id = bpy.data.objects["Controller"]
var.targets[0].transform_type = 'LOC_X'
var.targets[0].transform_space = 'WORLD_SPACE'
driver.expression = "ctrl * 3"  # also works on shape keys via sk.driver_add("value")

Examples

Example 1: Bouncing ball with squash and stretch

User request: "Animate a ball bouncing with squash and stretch"

python
import bpy

bpy.ops.object.select_all(action='SELECT')
bpy.ops.object.delete()
bpy.ops.mesh.primitive_uv_sphere_add(radius=0.5, location=(0, 0, 3))
ball = bpy.context.active_object
ball.name = "BouncingBall"

keyframes = [  # (frame, z_pos, scale_x, scale_y, scale_z)
    (1,  3.0, 1.0, 1.0, 1.0),    (12, 0.5, 1.0, 1.0, 1.0),     # fall
    (15, 0.3, 1.3, 1.3, 0.6),    (18, 0.5, 0.85, 0.85, 1.2),   # squash + stretch
    (30, 2.2, 1.0, 1.0, 1.0),    (42, 0.5, 1.0, 1.0, 1.0),     # apex + second fall
    (45, 0.3, 1.2, 1.2, 0.7),    (55, 1.5, 1.0, 1.0, 1.0),     # smaller bounce
    (62, 0.5, 1.0, 1.0, 1.0),                                    # settle
]
for frame, z, sx, sy, sz in keyframes:
    ball.location = (0, 0, z)
    ball.keyframe_insert(data_path="location", frame=frame)
    ball.scale = (sx, sy, sz)
    ball.keyframe_insert(data_path="scale", frame=frame)

for fc in ball.animation_data.action.fcurves:
    for kp in fc.keyframe_points:
        kp.interpolation = 'BEZIER'

bpy.context.scene.frame_end = 62
bpy.ops.wm.save_as_mainfile(filepath="/tmp/bouncing_ball.blend")

Example 2: Arm rig with IK reaching for an object

User request: "Create a simple arm rig with IK and animate it reaching for a cube"

python
import bpy

bpy.ops.object.select_all(action='SELECT')
bpy.ops.object.delete()

arm_data = bpy.data.armatures.new("ArmRig")
arm_obj = bpy.data.objects.new("ArmRig", arm_data)
bpy.context.collection.objects.link(arm_obj)
bpy.context.view_layer.objects.active = arm_obj
bpy.ops.object.mode_set(mode='EDIT')
prev = None
for name, head, tail in [("UpperArm",(0,0,1.5),(0.6,0,1.5)),
                          ("Forearm",(0.6,0,1.5),(1.2,0,1.5)),
                          ("Hand",(1.2,0,1.5),(1.4,0,1.5))]:
    b = arm_data.edit_bones.new(name)
    b.head, b.tail = head, tail
    if prev: b.parent, b.use_connect = prev, True
    prev = b
bpy.ops.object.mode_set(mode='OBJECT')

# IK target + constraint
bpy.ops.object.empty_add(type='PLAIN_AXES', location=(1.2, 0, 1.5))
ik_target = bpy.context.active_object
ik_target.name = "IK_Hand"
bpy.context.view_layer.objects.active = arm_obj
bpy.ops.object.mode_set(mode='POSE')
ik = arm_obj.pose.bones["Hand"].constraints.new('IK')
ik.target, ik.chain_count = ik_target, 3
bpy.ops.object.mode_set(mode='OBJECT')

# Animate IK target reaching toward a cube
bpy.ops.mesh.primitive_cube_add(size=0.3, location=(1.5, 0.5, 1.0))
for loc, frame in [((1.2,0,1.5),1), ((1.5,0.5,1.0),30), ((1.5,0.5,1.3),50)]:
    ik_target.location = loc
    ik_target.keyframe_insert(data_path="location", frame=frame)
for fc in ik_target.animation_data.action.fcurves:
    for kp in fc.keyframe_points:
        kp.interpolation, kp.easing = 'BEZIER', 'EASE_IN_OUT'
bpy.context.scene.frame_end = 50
bpy.ops.wm.save_as_mainfile(filepath="/tmp/arm_grab.blend")

Guidelines

  • data_path must match the RNA path exactly: "location", "rotation_euler", "scale", '["custom_prop"]'.
  • Armature workflow: Edit mode for bones (edit_bones), Pose mode for constraints and keyframes (pose.bones).
  • For IK, use Empty objects as targets. chain_count=0 solves the entire chain to root.
  • Shape keys need a "Basis" key first. Animate via key_blocks["Name"].value (0.0 to 1.0).
  • Interpolation: CONSTANT for hold/step, LINEAR for mechanical, BEZIER with easing for organic motion.
  • Set animation_data.action = None to let NLA strips drive — an active action overrides NLA.
  • For walk cycles, keyframe one stride and use a Cycles F-Curve modifier or NLA repeat to loop.
  • Bake constraints/drivers with bpy.ops.nla.bake() before export — other software cannot read them.

Information

Version
1.0.0
Author
terminal-skills
Category
Design
License
Apache-2.0

Use Cases

→Create 3D Animated Product Showcases with Blender