What's Layered Blend Per Bone?

An AnimBP node that blends an upper-body animation over a full-body base pose, isolating the blend to specific bone hierarchies (e.g., spine and above). Used for aim animations while running.

Why is my layered pose completely off?

Weight pin is 0 (no blend), Branch Filters list the wrong root bone, or the input pose is additive while the node expects full-body (or vice versa). Inspect the variable feeding Blend Weights and check the Branch Filters in node details.

What's the difference between Additive and Full Body mode?

Additive: the layered pose is an offset added to the base. Full Body: the layered pose replaces the base for the filtered bones. Mismatch produces wrong-looking results — e.g., adding a raised-arm offset onto an already-raised arm produces hyperextension.

Fix: Unreal AnimBP Pose Blend Zero Weight

Quick answer: Set the Blend Weights variable to 1.0, ensure Branch Filters reference the correct root bone (typically spine_01), and verify additive/full-body modes match the input pose authoring.

A character has a base locomotion (walk/run) and a layered “aim with rifle” pose that should override the upper body while preserving leg motion. The aim pose isn’t visible at all — only legs and arms hang down. The Layered Blend Per Bone exists but applies zero weight.

Layered Blend Per Bone Anatomy

The node takes:

Base Pose (input 0): the full-body pose to blend over.
Blend Poses (input array): one or more layered poses.
Blend Weights: array of floats, one per layered pose. 0 = no contribution, 1 = full override.
Branch Filters: per-pose configuration with root bone name and blend depth.

Fix 1: Check Blend Weights

// In Anim BP Event Graph
if (CharacterIsAiming) {
    AimBlendWeight = 1.0f;
} else {
    AimBlendWeight = 0.0f;
}

Wire AimBlendWeight to the Layered Blend Per Bone’s Blend Weights array (element 0). Default initialized to 0 = always off. Print the value during play to confirm it’s 1 when expected.

Fix 2: Branch Filters Root Bone

In the node’s Details, expand Branch Filters → [0] → Bone Name. For an upper-body blend, set to spine_01 (or your skeleton’s equivalent spine root). Blend Depth = -1 cascades to all child bones.

If Bone Name is empty or wrong, the filter doesn’t match any bones — the layered pose contributes 0 even when weight is 1.

Fix 3: Additive vs Full Body Mode

Check the Layered Pose property of each blend pose: Mesh Space, Mesh Space Additive, or Local Space. If your aim pose was authored as additive (relative to base) but the node treats it as full-body, the rotations are doubled-up.

Right-click → Convert to Additive on the AnimSequence asset to standardize. Or change the node’s expected mode to match the source.

Diagnose with Pose Debugging

Open the Anim BP. In Preview, drag the AimBlendWeight slider. The upper body should transition between base pose and aim pose. If nothing changes, recheck weights and filters.

Console: showdebug animation in PIE. Shows active animation nodes and their current weights.

Verifying

In PIE, set the aiming state. The character’s upper body should hold the aim pose while legs continue to run. Switch off aiming — upper body returns to the locomotion pose. Animation transitions smoothly via the weight lerp.

“Layered Blend needs weight, the right filter root, and matching pose modes. Three knobs to align.”

Use showdebug animation as your default diagnostic for any AnimBP weight bug — reveals weights in real time.