Why does my custom trace channel return default response?

Custom channel must be added in Project Settings → Engine → Collision → Trace Channels. Set Default Response. Per-object: edit Collision Profile to Block/Overlap your channel.

Object channel vs Trace channel?

Object Channel: tag for the body (Pawn, WorldStatic). Trace Channel: query type (Visibility, Camera, Weapon). Define and use both per use case.

Body collision profile combines channels. Custom profile in Project Settings is reusable across actors.

Fix: Custom Trace Channel Returns Default Response

Quick answer: Project Settings → Collision → New Trace Channel “Weapon”. Default Block. Per-actor profile uses it.

Bullet trace ignores walls. Custom Weapon trace channel exists; walls' profile didn’t respond.

The Fix

Project Settings → Engine → Collision:
  Trace Channels:
    + New Channel:    Weapon
      Default Response: Block

  Preset Collision Profiles:
    + WeaponBlockable
      Object Type:     WorldStatic
      Trace Responses:
        Weapon:        Block

Wall actor:
  Collision Profile: WeaponBlockable

Custom trace channel + per-profile response = explicit hit detection.

Verifying

LineTraceByChannel with Weapon: hits walls. Without channel definition: ignores or returns default.

“Define channel. Profile responds. Trace lands.”

Related Issues

For Physics asset trace, see physics trace. For Vehicle tire, see vehicle tire.

Channel + profile. Block right.