Blender rigging: armature, weights and IK, the basics step by step

A 3D model does not move on its own: to animate it, you need a skeleton that deforms it. That is rigging, the step between modelling and animation. This guide covers the basics in Blender, in the order you practise them: creating the armature, binding it to the mesh, correcting the weights, posing the character, adding inverse kinematics, then saving time with Rigify. Advanced cases, non-humanoid creatures and complex constraints, have their own tutorials (in French), linked at the end of the page.

Rigging vocabulary

• Armature: Blender's skeleton object, made of bones linked into chains.
• Parent and child bones: a child bone follows its parent; rotating the shoulder carries the arm and the hand with it.
• Skinning: the link between the mesh and the armature, which says which vertices follow which bones.
• Weights: the share of a bone's influence on a vertex, from 0 to 1, stored in vertex groups named after the bone.
• Constraints: rules that drive a bone, such as inverse kinematics or tracking a target.
• Rig: the whole set of skeleton, weights and controls, ready for the animator.

Step 1: create the armature

In Object Mode, Shift+A then Armature adds a first bone. Switch to Edit Mode (Tab): each bone has a head and a tail, and E extrudes a new bone from the selected tail, already connected to the previous one. Build the spine this way, then the neck, the head, an arm and a leg.

Name the bones on one side with the .L suffix (left) and those on the other side with .R (right): arm.L, forearm.L, hand.L. This convention then lets you generate the other side with Armature, Symmetrize, and copy a pose as a mirror image during animation. In the armature properties, the In Front option under Viewport Display shows the bones over the mesh, so you do not lose them inside the model.

Step 2: bind the mesh to the bones

In Object Mode, select the mesh, then the armature last (it becomes the active object), and press Ctrl+P. Under Armature Deform, there are three choices:

Blender adds an Armature modifier to the mesh: that is what deforms the model when the bones move. Automatic weights give a good starting point, but as the manual points out, on a complex armature some areas deform badly and need touching up by hand.

Step 3: correct the weights in Weight Paint

Select the armature, then the mesh, and switch to Weight Paint mode. The model is displayed in colours: red for full influence of the active bone, blue for none. You paint to add influence, remove it with the brush in subtract mode, and smooth the transitions with the Blur tool. The areas to watch are always the same: shoulders, armpits, elbows, knees, pelvis, and fingers that stick together.

Test by posing the character while you paint: bend the elbow to 90 degrees, raise the arm, and fix whatever pinches or stretches. A mesh with enough edge loops at the joints deforms much better, which is a matter of retopology (in French) before rigging.

Step 4: pose in Pose Mode

With the armature selected, Ctrl+Tab switches to Pose Mode. There you rotate and move bones with R and G as you would objects, and Alt+R, Alt+G reset the rotation and the position. The rest position of the armature, the one in Edit Mode, does not change: it is the reference from which every pose is calculated. Characters are in fact often modelled and rigged in a T-pose or an A-pose, arms out, so that the weights are calculated cleanly.

Step 5: inverse kinematics (IK)

By default, you animate in forward kinematics (FK): you rotate the thigh, then the shin, then the foot. To keep a foot planted on the ground while the body moves, inverse kinematics is more practical. Add an Inverse Kinematics constraint to the shin bone (bone constraints tab) and set:

• Target: the object or bone the chain should point to, usually a foot control bone, not connected to the others.
• Pole Target: the object or bone that orients the chain, placed in front of the knee to decide which way it bends.
• Chain Length: the number of bones affected, counting up from the constrained bone, 2 for thigh and shin.

When you move the control bone, the whole leg follows and the knee bends by itself. Do the same for the arms when a hand has to stay on an object. The other useful constraints (Copy Rotation, Damped Track, Stretch To, rotation limits) are covered in detail in the tutorial on complex rigging constraints (in French).

Saving time with Rigify

Building a complete character rig by hand, with FK/IK switching, spine controls and fingers, takes days. Rigify, an add-on documented in the Blender manual and enabled in Preferences, under Add-ons, does it in three steps:

1. Add a meta-rig with Shift+A, Armature: Basic Human, Human, Cat, Wolf, Horse or Shark.
2. Adjust the bones of the meta-rig to the character's proportions, in Edit Mode or in Pose Mode.
3. Generate the rig with the Generate Rig button, at the bottom of the Armature tab, in Object Mode. The mesh is then bound to the generated rig with Ctrl+P and automatic weights.

Keep the meta-rig: if something needs fixing, you edit it and generate again, and Rigify replaces the rig while keeping the modifiers and constraints. For a ready-made animation rather than a rig, the Mixamo library automatically rigs and animates a humanoid character: see the Mixamo glossary entry (in French).

Common mistakes

• The object's scale has not been applied. A character scaled up in Object Mode deforms badly: apply the scale with Ctrl+A before binding the mesh.
• Badly oriented bones. A bone that rotates around its own axis (roll) differently from its neighbour gives unpredictable rotations; recalculate the roll in Edit Mode.
• Automatic weights fail on a mesh made of parts that intersect or are not closed: clean up the mesh, or paint the weights by hand.
• The mesh does not follow the armature because it has no Armature modifier, or its vertex groups do not carry exactly the names of the bones.

To go further, the tutorial on rigging non-humanoid creatures (in French) covers quadrupeds and appendages, and the Blender animation guide (in French) moves on to setting keyframes.