# \#interface **URL:** https://forums.unrealengine.com/tag/interface/650.md [Latest](https://forums.unrealengine.com/latest.md) · [Categories](https://forums.unrealengine.com/categories.md) · [Tags](https://forums.unrealengine.com/tags.md) --- ## [\[Blueprints\] How to add delegate parameter to interface function?](https://forums.unrealengine.com/t/blueprints-how-to-add-delegate-parameter-to-interface-function/479965)
**Author:** [@Joseph\_Fawzy](https://forums.unrealengine.com/u/Joseph_Fawzy)\ **Replies:** 12\ **Last updated:** [October 14, 2026, 4:17pm UTC](https://forums.unrealengine.com/t/blueprints-how-to-add-delegate-parameter-to-interface-function/479965 "2026-10-14T16:17:37Z")
Hi We are trying to move our implementation to the “Implement to interfaces” paradigm, where everything is an implementation on an interface Interfaces cannot have “event dispatchers”, so we tried to pass the event to … --- ## [Stuck with a "None" interface entry in Blueprint](https://forums.unrealengine.com/t/stuck-with-a-none-interface-entry-in-blueprint/2719568)
**Author:** [@mykola](https://forums.unrealengine.com/u/mykola)\ **Replies:** 3\ **Last updated:** [May 2, 2026, 7:55pm UTC](https://forums.unrealengine.com/t/stuck-with-a-none-interface-entry-in-blueprint/2719568 "2026-05-02T19:55:52Z")
Hey everyone, I deleted an interface asset from my project, but now one of my Blueprints has a broken None entry.I can’t remove it there’s no delete button showing up for it, and it’s just sitting there as None. Fix Up … --- ## [Mask Background Blur Widget](https://forums.unrealengine.com/t/mask-background-blur-widget/769695)
**Author:** [@TijerinArtStudio](https://forums.unrealengine.com/u/TijerinArtStudio)\ **Replies:** 5\ **Last updated:** [March 17, 2026, 10:12am UTC](https://forums.unrealengine.com/t/mask-background-blur-widget/769695 "2026-03-17T10:12:16Z")
Hello! I have tried all the ways I could think of to mask a “Background Blur Widget” to get the result you see in the image: But I have been unable, I think the problem is that I don’t know how to use the image sect… --- ## [Input Actions in the Game menu using "Set Input Mode UI Only"](https://forums.unrealengine.com/t/input-actions-in-the-game-menu-using-set-input-mode-ui-only/2499964)
**Author:** [@Jowoosa1](https://forums.unrealengine.com/u/Jowoosa1)\ **Replies:** 4\ **Last updated:** [February 19, 2026, 4:29pm UTC](https://forums.unrealengine.com/t/input-actions-in-the-game-menu-using-set-input-mode-ui-only/2499964 "2026-02-19T16:29:12Z")
Im making the game menus (inventory, pause, equipment) and I was working with two “Input Mapping Contex”, one for Gameplay and the other one for the UI navigation. When i load a menu, i add the UI Mapping Context with a… --- ## [Ideal approach for same actor, component communication (Design Problem)](https://forums.unrealengine.com/t/ideal-approach-for-same-actor-component-communication-design-problem/2687061)
**Author:** [@TonyStarchXD](https://forums.unrealengine.com/u/TonyStarchXD)\ **Replies:** 0\ **Last updated:** [December 23, 2025, 12:28am UTC](https://forums.unrealengine.com/t/ideal-approach-for-same-actor-component-communication-design-problem/2687061 "2025-12-23T00:28:30Z")
I am looking for advice on how to aproach the following design problem in UE5 blueprints with a focus on modularity, maintainability and scalability: The GameMovementComponent There exists an actor component attached t… --- ## [Engine's UI - Docking to Sidebar](https://forums.unrealengine.com/t/engines-ui-docking-to-sidebar/1785192)
**Author:** [@Barabulyko](https://forums.unrealengine.com/u/Barabulyko)\ **Replies:** 1\ **Last updated:** [December 7, 2025, 10:46am UTC](https://forums.unrealengine.com/t/engines-ui-docking-to-sidebar/1785192 "2025-12-07T10:46:21Z")
Hello! I have a little feedback regarding Editor’s UI, namely regarding Sidebars. Recently I decided to switch into having everything hidden in sidebars because I’v grew with amount of windows present and all those tab… --- ## [I want to make an interface that calls some functions whenever a derived class created.](https://forums.unrealengine.com/t/i-want-to-make-an-interface-that-calls-some-functions-whenever-a-derived-class-created/2676835)
**Author:** [@E\_Hamza\_MB](https://forums.unrealengine.com/u/E_Hamza_MB)\ **Replies:** 4\ **Last updated:** [November 21, 2025, 4:00am UTC](https://forums.unrealengine.com/t/i-want-to-make-an-interface-that-calls-some-functions-whenever-a-derived-class-created/2676835 "2025-11-21T04:00:59Z")
I want to design an interface in Unreal Engine. It is important for me to have immediate access to the functions implemented by this interface. What I want is for every class that implements this interface to automatical… --- ## [How to get an interface pointer variable to work w/UPROPERTY()](https://forums.unrealengine.com/t/how-to-get-an-interface-pointer-variable-to-work-w-uproperty/383017)
**Author:** [@YawLighthouse](https://forums.unrealengine.com/u/YawLighthouse)\ **Replies:** 17\ **Last updated:** [November 4, 2025, 3:54am UTC](https://forums.unrealengine.com/t/how-to-get-an-interface-pointer-variable-to-work-w-uproperty/383017 "2025-11-04T03:54:32Z")
Hello, I am attempting to have an interface pointer variable that is declared in the header be VisibleAnywhere, BlueprintReadOnly in the UPROPERTY() but when I compile it gives me an error: UPROPERTY pointers cannot be … --- ## [Class-independent event dispatcher?](https://forums.unrealengine.com/t/class-independent-event-dispatcher/2657083)
**Author:** [@Extrahdmi](https://forums.unrealengine.com/u/Extrahdmi)\ **Replies:** 15\ **Last updated:** [September 21, 2025, 9:05am UTC](https://forums.unrealengine.com/t/class-independent-event-dispatcher/2657083 "2025-09-21T09:05:33Z")
Event dispatchers are essential for an event-driven approach, but their dependency on classes can sometimes be quite difficult to use. Is there an event dispatcher that is implemented like an interface and can be used by… --- ## [Interfaces and event dispatchers](https://forums.unrealengine.com/t/interfaces-and-event-dispatchers/2638314)
**Author:** [@Stachu1234q2](https://forums.unrealengine.com/u/Stachu1234q2)\ **Replies:** 7\ **Last updated:** [August 12, 2025, 9:40am UTC](https://forums.unrealengine.com/t/interfaces-and-event-dispatchers/2638314 "2025-08-12T09:40:03Z")
Hi everyone, I’ve been reworking my UI to use event dispatchers (i was mainly using interfaces before) but I don’t know if I’m doing this correctly. This is what my main ui widget looks like: I’ve been always told t… --- ## [Inherited Interface Disappears From Third SubClass After Clicking on All Function Names in MyBlueprint Tab](https://forums.unrealengine.com/t/inherited-interface-disappears-from-third-subclass-after-clicking-on-all-function-names-in-myblueprint-tab/2491281)
**Author:** [@Doctor\_Kannon](https://forums.unrealengine.com/u/Doctor_Kannon)\ **Replies:** 3\ **Last updated:** [August 4, 2025, 9:47pm UTC](https://forums.unrealengine.com/t/inherited-interface-disappears-from-third-subclass-after-clicking-on-all-function-names-in-myblueprint-tab/2491281 "2025-08-04T21:47:33Z")
Bug Report Steps to Reproduce: Assign an interface to a class. Verify that the interface is inherited in one, two, and three subclasses. In the third subclass, click on the inherited interface function names under the… --- ## [Interface Functions are getting cleared/deleted after Editor Restart](https://forums.unrealengine.com/t/interface-functions-are-getting-cleared-deleted-after-editor-restart/2610881)
**Author:** [@neonedekry1](https://forums.unrealengine.com/u/neonedekry1)\ **Replies:** 1\ **Last updated:** [July 19, 2025, 9:13pm UTC](https://forums.unrealengine.com/t/interface-functions-are-getting-cleared-deleted-after-editor-restart/2610881 "2025-07-19T21:13:34Z")
I’ve been seeing 5 year old posts about this, and its still an huge issue and it makes everything so frustrating to develop new things in Unreal Engine. Anybody found a fix about this issue? Steps to reproduce: Create… --- ## [How to send interface messages to individual NPCs from UI Widgets without hardcoding references?](https://forums.unrealengine.com/t/how-to-send-interface-messages-to-individual-npcs-from-ui-widgets-without-hardcoding-references/2586679)
**Author:** [@e7de84f7c71249dc8a21a7d1f05899f3](https://forums.unrealengine.com/u/e7de84f7c71249dc8a21a7d1f05899f3)\ **Replies:** 5\ **Last updated:** [July 2, 2025, 6:30am UTC](https://forums.unrealengine.com/t/how-to-send-interface-messages-to-individual-npcs-from-ui-widgets-without-hardcoding-references/2586679 "2025-07-02T06:30:29Z")
Hi everyone, I’m working on a dialogue system using Blueprints in Unreal Engine, and I have a question about communication between a UI Widget and NPC actors via a Blueprint Interface. Here’s the situation: I ha… --- ## [Window \> Developer Tools \> Modules not found](https://forums.unrealengine.com/t/window-developer-tools-modules-not-found/451877)
**Author:** [@anonymous\_user\_1c979218](https://forums.unrealengine.com/u/anonymous_user_1c979218)\ **Replies:** 7\ **Last updated:** [June 19, 2025, 5:36am UTC](https://forums.unrealengine.com/t/window-developer-tools-modules-not-found/451877 "2025-06-19T05:36:53Z")
When using UE4 (ver.4.22.3) I can’t open “modules” dialog because there is no option “Window \> Developer Tools \> Modules”. Why I cannot find this option? On the other hand, UE4 (ver.4.19.2 on my same machine) has “Modul… --- ## [\[UMG\] Widgets overlap Mobile default touch interface. A way around it?](https://forums.unrealengine.com/t/umg-widgets-overlap-mobile-default-touch-interface-a-way-around-it/297381)
**Author:** [@JakobR](https://forums.unrealengine.com/u/JakobR)\ **Replies:** 5\ **Last updated:** [June 16, 2025, 7:39am UTC](https://forums.unrealengine.com/t/umg-widgets-overlap-mobile-default-touch-interface-a-way-around-it/297381 "2025-06-16T07:39:57Z")
UE4 v4.5. A UMG widgets which has content in the same position as the mobile touch interface will render the touch interface obsolete. It overlaps and takes priority of over the default mobile touch interface. Is there … --- ## [Best way to break up Blueprint Interfaces](https://forums.unrealengine.com/t/best-way-to-break-up-blueprint-interfaces/2489183)
**Author:** [@Zapking9224](https://forums.unrealengine.com/u/Zapking9224)\ **Replies:** 8\ **Last updated:** [May 5, 2025, 3:43am UTC](https://forums.unrealengine.com/t/best-way-to-break-up-blueprint-interfaces/2489183 "2025-05-05T03:43:03Z")
Hi! So I’m going through my project looking for different optimization and just overall better approaches to things that I had done a couple years ago when I first started this project. Right now, I’m focusing on how to … --- ## [MAIN MENU BACKGROUND ISSUE](https://forums.unrealengine.com/t/main-menu-background-issue/2462571)
**Author:** [@Cykablatta](https://forums.unrealengine.com/u/Cykablatta)\ **Replies:** 27\ **Last updated:** [April 19, 2025, 7:22am UTC](https://forums.unrealengine.com/t/main-menu-background-issue/2462571 "2025-04-19T07:22:54Z")
Hello ev! :slightly\_smiling\_face: I created an empty layer that only has a widget to show the main menu. But when I simulate the level to display it, it looks like the image is not in the foreground, like its opacity is… --- ## [\[Guide\] Project World To Screen Bidirectional (Blueprint Method)](https://forums.unrealengine.com/t/guide-project-world-to-screen-bidirectional-blueprint-method/2461963)
**Author:** [@petriell01](https://forums.unrealengine.com/u/petriell01)\ **Replies:** 0\ **Last updated:** [April 17, 2025, 7:45pm UTC](https://forums.unrealengine.com/t/guide-project-world-to-screen-bidirectional-blueprint-method/2461963 "2025-04-17T19:45:54Z")
an alternative to the ‘Project World to Screen space’ node. designed to simulate a projection outside the camera frustum. customizable, can contain margins (offset from the screen edges), and steps (projection preci… --- ## [Change 3d View Navigation](https://forums.unrealengine.com/t/change-3d-view-navigation/2460503)
**Author:** [@RyanKingArt](https://forums.unrealengine.com/u/RyanKingArt)\ **Replies:** 1\ **Last updated:** [April 17, 2025, 12:23am UTC](https://forums.unrealengine.com/t/change-3d-view-navigation/2460503 "2025-04-17T00:23:29Z")
Problem Solved, See my Reply Below. I was checking out a 3d model on FAB and opened the 3d viewer. A new option popped up on the screen asking me if I wanted the regular orbit navigation, or unreal engine navigation. I… --- ## [Interface Error](https://forums.unrealengine.com/t/interface-error/2404563)
**Author:** [@blAddddDe](https://forums.unrealengine.com/u/blAddddDe)\ **Replies:** 6\ **Last updated:** [March 21, 2025, 8:24pm UTC](https://forums.unrealengine.com/t/interface-error/2404563 "2025-03-21T20:24:38Z")
Hi! When trying to build the project the following error pops up: PlayerInterface.gen.cpp(106): Error C2511 : void IPlayerInterface::Equip(USkeletalMesh \*,EEquipmentID,const TArray\ **Author:** [@enam1984](https://forums.unrealengine.com/u/enam1984)\ **Replies:** 1\ **Last updated:** [March 9, 2025, 12:10pm UTC](https://forums.unrealengine.com/t/new-to-interfaces-trying-to-pass-mouse-values-to-another-class-anim-class/2381133 "2025-03-09T12:10:43Z") Hey All, I’m trying to pass mouse values from my Character Class to my Anim class I have an Interface with the function declared which i have created to capture mouse values. I have created the interface function in m… --- ## [Interface not firing in Standalone](https://forums.unrealengine.com/t/interface-not-firing-in-standalone/2364684)
**Author:** [@Virtuality](https://forums.unrealengine.com/u/Virtuality)\ **Replies:** 1\ **Last updated:** [March 7, 2025, 9:53am UTC](https://forums.unrealengine.com/t/interface-not-firing-in-standalone/2364684 "2025-03-07T09:53:49Z")
Hi everyone, I’m upgrading from UE5.4 to UE5.5 and it’s been a world of trouble so far (mostly with UMG). My latest issue is Interfaces. It seems certain interfaces are firing fine in PIE mode, but are completely faili… --- ## [RPC in Character Actor Component](https://forums.unrealengine.com/t/rpc-in-character-actor-component/2345138)
**Author:** [@Space\_Grouse](https://forums.unrealengine.com/u/Space_Grouse)\ **Replies:** 8\ **Last updated:** [February 21, 2025, 1:41pm UTC](https://forums.unrealengine.com/t/rpc-in-character-actor-component/2345138 "2025-02-21T13:41:00Z")
I have a blueprint interface for handling interactions that I have added to my character. The interface includes a RPC to the server and within the RPC sends a call to the actor interacted with. The problem is the RPC is… --- ## [Difference between "Interface Call" and "Interface Message"](https://forums.unrealengine.com/t/difference-between-interface-call-and-interface-message/323826)
**Author:** [@anonymous\_user\_fd57f212](https://forums.unrealengine.com/u/anonymous_user_fd57f212)\ **Replies:** 15\ **Last updated:** [February 5, 2025, 9:46pm UTC](https://forums.unrealengine.com/t/difference-between-interface-call-and-interface-message/323826 "2025-02-05T21:46:49Z")
Using Interfaces, you can use the Interface Message and the Interface Call node (I always use Message). However it would be good to know the difference between these two nodes. For somebody who knows the answer, this is… --- ## [I need to feed values from my MainFireArmBP to my another BP called BP\_Rifle](https://forums.unrealengine.com/t/i-need-to-feed-values-from-my-mainfirearmbp-to-my-another-bp-called-bp-rifle/2302696)
**Author:** [@siqso\_99](https://forums.unrealengine.com/u/siqso_99)\ **Replies:** 1\ **Last updated:** [January 25, 2025, 6:37pm UTC](https://forums.unrealengine.com/t/i-need-to-feed-values-from-my-mainfirearmbp-to-my-another-bp-called-bp-rifle/2302696 "2025-01-25T18:37:53Z")
I’d like to spawn a projectile from my BP\_Rifle and i would need some variables such as muzzle location, velocity, etc from my MainFireArmBP. Main reason i want to spaw the projectile on my BP\_Rifle is because i would… --- ## [Interface function replication](https://forums.unrealengine.com/t/interface-function-replication/315041)
**Author:** [@Justin.Dooley](https://forums.unrealengine.com/u/Justin.Dooley)\ **Replies:** 56\ **Last updated:** [January 24, 2025, 1:19am UTC](https://forums.unrealengine.com/t/interface-function-replication/315041 "2025-01-24T01:19:07Z")
In a related question server-only-function-replication-does-not-fire I came across what seemed to be a straightforward task and that was to ensure that my objects could be easily reused. Because they are network capable … --- ## [Must I check for an implemented interface on an object when executing a function by message?](https://forums.unrealengine.com/t/must-i-check-for-an-implemented-interface-on-an-object-when-executing-a-function-by-message/2273273)
**Author:** [@Maladrum](https://forums.unrealengine.com/u/Maladrum)\ **Replies:** 2\ **Last updated:** [January 12, 2025, 5:01pm UTC](https://forums.unrealengine.com/t/must-i-check-for-an-implemented-interface-on-an-object-when-executing-a-function-by-message/2273273 "2025-01-12T17:01:25Z")
I’ve been developing with Unreal for a long time, and one feature I enjoy using is Blueprint Interfaces. However, I ran into a curiosity I can’t find an answer for. I’m wondering if, before telling an object to call an … --- ## [Calling Interface Functions In C++](https://forums.unrealengine.com/t/calling-interface-functions-in-c/323521)
**Author:** [@Havoc47c](https://forums.unrealengine.com/u/Havoc47c)\ **Replies:** 11\ **Last updated:** [January 7, 2025, 2:39pm UTC](https://forums.unrealengine.com/t/calling-interface-functions-in-c/323521 "2025-01-07T14:39:53Z")
I am trying to implement an interaction system via an interface but am having trouble figuring out how to call functions in my interface via C++. I am able to call these interface functions in Blueprints with the message… --- ## [Error: C++ Default parameter not parsed: "nullptr"](https://forums.unrealengine.com/t/error-c-default-parameter-not-parsed-nullptr/385328)
**Author:** [@anonymous\_user\_1ed1c3df](https://forums.unrealengine.com/u/anonymous_user_1ed1c3df)\ **Replies:** 9\ **Last updated:** [December 21, 2024, 4:54pm UTC](https://forums.unrealengine.com/t/error-c-default-parameter-not-parsed-nullptr/385328 "2024-12-21T16:54:42Z")
I have a UFUNCTION that takes in a type of TScriptableInterface as one of its parameters. In the header, I have default values set for everything so when called in blueprint the function node has the defaults auto-filled… --- ## [Interface NetMulticast function only runs on Server](https://forums.unrealengine.com/t/interface-netmulticast-function-only-runs-on-server/2161303)
**Author:** [@Domnias](https://forums.unrealengine.com/u/Domnias)\ **Replies:** 2\ **Last updated:** [December 1, 2024, 4:13pm UTC](https://forums.unrealengine.com/t/interface-netmulticast-function-only-runs-on-server/2161303 "2024-12-01T16:13:27Z")
It seems to me that interface functions marked as NetMulticast defined in C++ only run on the Server when invoked from the Server. I made an example: test\_if.h #pragma once #include "CoreMinimal.h" #include "system/u… [Next page](https://forums.unrealengine.com/tag/interface/650.md?match_all_tags=true&page=1&tags%5B%5D=interface)