To control how objects interact in Unreal Engine, set collision presets for each object, test them in play to verify block, overlap, and ignore behavior, and adjust hit or overlap event wiring as needed. For custom logic and larger projects, review collision channels and presets in Project Settings and set default profiles in Blueprint or C++ for reusable setup.
Start with object types and response channels
You manage collision in Unreal Engine using two main concepts: Object Type and Response Channels. The object type tells Unreal what kind of thing your object is in the world, such as World Static or Pawn. The response channels control whether your object chooses to block, overlap, or ignore other object types.
To edit these directly, set the Collision Presets dropdown to Custom in the details panel. This unlocks the fields for adjusting how your object responds to each type.
The Collision settings panel shows the preset dropdown set to Custom and the response fields below it. — Keltick's Game Dev
- Block prevents two objects from passing through each other if both sides are set to block.
- Overlap allows objects to pass through, but overlap events can still be triggered for logic.
You can set up these responses on a per-object basis or design project-wide presets.
Test block, overlap, and ignore in Play mode
Once you’ve assigned collision presets, always check how they behave in play. If both objects are set to block, they will not pass through each other. If one is set to block and the other to ignore, the object set to ignore will pass right through.
If two objects’ types or responses do not match (for example, a wall set to block colliding with a player set to ignore), you may see unexpected results in play.
The Unreal Engine editor shows a selected cube actor in the level viewport with collision settings open on the right. — Keltick's Game Dev
This kind of careful alignment and testing prevents errors like a player phasing through a wall or receiving no collision event when one is needed.
Use hit events to react when objects collide
When an object with blocking collision contacts something else, Unreal can fire a hit event. In Blueprints, this is typically handled with an On Component Hit event node.
Wiring this node allows you to react to collisions, print debug output, or trigger gameplay actions. The event provides valuable data such as which other actor or component was involved in the collision.
The Blueprint event graph shows an On Component Hit event wired to a Print String node. — Keltick's Game Dev
Hit events only trigger when blocking collisions occur, not with overlaps.
Switch from hit events to overlap behavior when needed
Sometimes, you want objects to pass through one another but still react when they overlap. Switching from block to overlap changes the interaction. When a collision preset is set to overlap, hitting another object of the appropriate type will no longer trigger a hit event, but it can fire an overlap event instead.
Collision can also be set so the object ignores everything.
The Details panel shows the Collision Presets dropdown opened with OverlapAll highlighted. — Keltick's Game Dev
before after
Hit Event Response (Block)
- When set to block, hitting another blocked object triggers a hit event and can stop movement.
Overlap Behavior
- When set to overlap, hit events do not trigger; objects pass through each other, but overlap events can fire.
Open Project Settings to edit collision presets and channels
For advanced or project-wide collision control, open Project Settings and find the Collision section under Engine. Here you can see all defined object channels, trace channels, and collision presets.
You can add new channels or presets to customize how collision works for your specific needs.
Project Settings is open to Engine Collision with object channels and trace channels visible, plus a collapsed Preset section. — Keltick's Game Dev
This approach is essential for larger projects where reusing collision behaviors helps avoid mistakes.
Set default collision profiles in Blueprint or C++
You can save effort and enforce consistency by setting collision profiles automatically in your C++ constructors or in Blueprint setup. Each component (such as a collider or mesh) can have its own profile.
To do this in C++, call the collision profile assignment method and pass the name of the preset exactly (profile names are case-sensitive).
// Example: Setting default collision profiles for components in a C++ constructor
// Set the collider to BlockAll
Collider->SetCollisionProfileName(FName("BlockAll"));
// Set the mesh to NoCollision
Mesh->SetCollisionProfileName(FName("NoCollision"));
A C++ editor displays component setup code with an autocomplete menu for collision profile methods. — Keltick's Game Dev
Using default profiles streamlines setup and ensures new blueprints start with correct collision.
FAQ
how to add collision in Unreal Engine
Open the object's details panel, find the Collision Presets dropdown, and choose or customize a profile. Setting the preset to Custom unlocks per-channel responses for blocking, overlapping, or ignoring specific object types.
Unreal Engine blueprint overlap tutorial
Set an object's Collision Preset to an overlap mode (like OverlapAll). Then, use On Component Begin Overlap events in your Blueprint to react when other actors enter its area.
Unreal Engine physics basics
Unreal Engine handles collision using object types and collision responses (block, overlap, ignore). By setting these correctly, you can create physical behaviors like solid objects, triggers, or pass-through areas that interact according to your gameplay logic.
Unreal Engine interaction system guide
Use hit and overlap events to build interactive systems. For example, detect when a player collides with or overlaps an object, then fire events in Blueprints to trigger game actions (like opening doors or collecting items).
Unreal Engine character collision setup
Character collision typically involves setting the capsule or root collider to block the environment and defining responses to other object types. Assign the correct object type (like Pawn for the character) and response profile to ensure the character interacts as intended with walls, floors, and triggers.
Sources
Official reference: Unreal Engine documentation.
Sources
Screenshots on this page are frames from the videos below, used to illustrate the steps they describe. All rights remain with their creators.
- The Fundamentals of Collision for Unreal Engine 5 | UE5 Collision Basics — Keltick's Game Dev, December 2, 2024
Checked against: