# \#interfaces **URL:** https://forums.unrealengine.com/tag/interfaces/4367.md [Latest](https://forums.unrealengine.com/latest.md) · [Categories](https://forums.unrealengine.com/categories.md) · [Tags](https://forums.unrealengine.com/tags.md) --- ## [My Blueprint -\> Interfaces -\> Does not show up on children](https://forums.unrealengine.com/t/my-blueprint-interfaces-does-not-show-up-on-children/361342)
**Author:** [@Fritsl](https://forums.unrealengine.com/u/Fritsl)\ **Replies:** 10\ **Last updated:** [April 1, 2025, 9:06pm UTC](https://forums.unrealengine.com/t/my-blueprint-interfaces-does-not-show-up-on-children/361342 "2025-04-01T21:06:59Z")
Basically the title should explain it all :slight\_smile: My Blueprint → Interfaces → Does not show up on children. Also, certain ‘Yellow warnings’ (for instance if you first set up an Interface as a function (W in/outp… --- ## [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… --- ## [How is this boolean possibly returning false?](https://forums.unrealengine.com/t/how-is-this-boolean-possibly-returning-false/2057200)
**Author:** [@Kotaru\_1](https://forums.unrealengine.com/u/Kotaru_1)\ **Replies:** 3\ **Last updated:** [October 7, 2024, 4:43pm UTC](https://forums.unrealengine.com/t/how-is-this-boolean-possibly-returning-false/2057200 "2024-10-07T16:43:10Z")
I have an interface with a boolean value that always returns false, even if literal This breakpoint gets triggered, and when I continue the execution it takes me to the matching event in this actor The boolean th… --- ## [\[Blueprint\] Get ( first ) Actor With Interface](https://forums.unrealengine.com/t/blueprint-get-first-actor-with-interface/2013030)
**Author:** [@VeganApps](https://forums.unrealengine.com/u/VeganApps)\ **Replies:** 4\ **Last updated:** [September 9, 2024, 11:04am UTC](https://forums.unrealengine.com/t/blueprint-get-first-actor-with-interface/2013030 "2024-09-09T11:04:29Z")
I try to create a function to automatically get the first Actor with a specific Interface in the scene but I don’t know how to set the parameter type to “Interface” class. The “Interface” type seems to exists but it … --- ## [Soft reference in interfaces creates hard reference dependecy](https://forums.unrealengine.com/t/soft-reference-in-interfaces-creates-hard-reference-dependecy/1890734)
**Author:** [@TheFlyingEpergne](https://forums.unrealengine.com/u/TheFlyingEpergne)\ **Replies:** 9\ **Last updated:** [June 5, 2024, 1:39pm UTC](https://forums.unrealengine.com/t/soft-reference-in-interfaces-creates-hard-reference-dependecy/1890734 "2024-06-05T13:39:49Z")
I have a BPI\_Interact interface This is what it looks like in the reference viewer with no references and therefore no dependencies When I add a SOFT reference, the reference viewer now looks like this Why??? P… --- ## [Any reading material on Blueprints Communication?](https://forums.unrealengine.com/t/any-reading-material-on-blueprints-communication/1714413)
**Author:** [@nmiles2go](https://forums.unrealengine.com/u/nmiles2go)\ **Replies:** 2\ **Last updated:** [February 26, 2024, 9:22pm UTC](https://forums.unrealengine.com/t/any-reading-material-on-blueprints-communication/1714413 "2024-02-26T21:22:20Z")
I want to read them because I am tired of watching tutorials to learn the nuances of each type of blueprint communication system in Unreal. Blueprints, Interfaces, Event dispatchers all of it. I just can’t seem to unders… --- ## [why does it say "Found more than one function with the same name BatteryResponse"?](https://forums.unrealengine.com/t/why-does-it-say-found-more-than-one-function-with-the-same-name-batteryresponse/1425752)
**Author:** [@DonJuan1232](https://forums.unrealengine.com/u/DonJuan1232)\ **Replies:** 2\ **Last updated:** [November 27, 2023, 3:07pm UTC](https://forums.unrealengine.com/t/why-does-it-say-found-more-than-one-function-with-the-same-name-batteryresponse/1425752 "2023-11-27T15:07:09Z")
So I want to make a mechanic where the player can pick up a Battery. But I get this error when I want to compile the Battery. If you can help that would be great or if you can show me a better way to do this. Thank yo… --- ## [Blueprint only listening to message when placed inworld?](https://forums.unrealengine.com/t/blueprint-only-listening-to-message-when-placed-inworld/1171084)
**Author:** [@bitsnuggle](https://forums.unrealengine.com/u/bitsnuggle)\ **Replies:** 7\ **Last updated:** [May 19, 2023, 11:58am UTC](https://forums.unrealengine.com/t/blueprint-only-listening-to-message-when-placed-inworld/1171084 "2023-05-19T11:58:13Z")
Hi there! I have implemented an interface into an actor blueprint. When I am trying to trigger a message with a simple input from the player controller, the interface message is recieved ONLY when I place the blueprint … --- ## [BP Interface for passing variable between 2 blueprints](https://forums.unrealengine.com/t/bp-interface-for-passing-variable-between-2-blueprints/880878)
**Author:** [@cnapsys](https://forums.unrealengine.com/u/cnapsys)\ **Replies:** 7\ **Last updated:** [April 9, 2023, 7:08pm UTC](https://forums.unrealengine.com/t/bp-interface-for-passing-variable-between-2-blueprints/880878 "2023-04-09T19:08:40Z")
Need a bit more assistance tweaking some of my BPs. Here’s what I am trying to accomplish: When a bullet hits a target, the target is destroyed and spawns a nice explosion effect. all fine and dandy. However, I am try… --- ## [Possible bug with BP interfaces? Or just me being a noob?](https://forums.unrealengine.com/t/possible-bug-with-bp-interfaces-or-just-me-being-a-noob/736602)
**Author:** [@cnapsys](https://forums.unrealengine.com/u/cnapsys)\ **Replies:** 3\ **Last updated:** [December 28, 2022, 2:02pm UTC](https://forums.unrealengine.com/t/possible-bug-with-bp-interfaces-or-just-me-being-a-noob/736602 "2022-12-28T14:02:42Z")
So, I was following the tutorial for building the brick breaker game when I noticed something that does not show up in my editor… I created a BP for the brick and a bp interface like shown in the tutorial. However, Aft… --- ## [Passing variables between blueprints](https://forums.unrealengine.com/t/passing-variables-between-blueprints/320845)
**Author:** [@anonymous\_user\_f353f08f1](https://forums.unrealengine.com/u/anonymous_user_f353f08f1)\ **Replies:** 5\ **Last updated:** [May 19, 2022, 10:30pm UTC](https://forums.unrealengine.com/t/passing-variables-between-blueprints/320845 "2022-05-19T22:30:35Z")
Please can someone help me with something, i have huge problems trying to pass variables between blueprints. I seems to spend days trying to get this working and i always end up in the same situation. All i want todo is… --- ## [Casting to a UInterface implemented in native code](https://forums.unrealengine.com/t/casting-to-a-uinterface-implemented-in-native-code/489397)
**Author:** [@anonymous\_user\_e8e17e55](https://forums.unrealengine.com/u/anonymous_user_e8e17e55)\ **Replies:** 0\ **Last updated:** [September 30, 2021, 11:08pm UTC](https://forums.unrealengine.com/t/casting-to-a-uinterface-implemented-in-native-code/489397 "2021-09-30T23:08:09Z")
What does this topic explains? Actually I am studying unreal engine with “Ue4 Scripting with c++ cookbook” by PACKT publication. And I can’t understand what this topic is trying to explain… See the topic under this h… --- ## [Can't communicate with parent of child blueprint from another blueprint.](https://forums.unrealengine.com/t/cant-communicate-with-parent-of-child-blueprint-from-another-blueprint/486672)
**Author:** [@coosadog](https://forums.unrealengine.com/u/coosadog)\ **Replies:** 4\ **Last updated:** [July 27, 2021, 8:21pm UTC](https://forums.unrealengine.com/t/cant-communicate-with-parent-of-child-blueprint-from-another-blueprint/486672 "2021-07-27T20:21:25Z")
If BPA contains a child of type BPB, then to get to that blueprint’s events, we need Yes, read it a weep. Inheritance works just fine, but child actor blueprints are best avoided… PS: you drag a pin from the child a… --- ## [How access variables or actors from level blueprint](https://forums.unrealengine.com/t/how-access-variables-or-actors-from-level-blueprint/482190)
**Author:** [@ProgrammingPaul](https://forums.unrealengine.com/u/ProgrammingPaul)\ **Replies:** 3\ **Last updated:** [April 20, 2021, 8:58am UTC](https://forums.unrealengine.com/t/how-access-variables-or-actors-from-level-blueprint/482190 "2021-04-20T08:58:01Z")
I have a blueprint actor within my scene called HoverSwitch. When a player shoots the HoverSwitch the switch changes a variable called FogScale in the level blueprint. FogScale is on tick and each second it changes the f… --- ## [Binding a multicast dynamic delegate via BlueprintNativeEvent from a blueprintable native interface?](https://forums.unrealengine.com/t/binding-a-multicast-dynamic-delegate-via-blueprintnativeevent-from-a-blueprintable-native-interface/480102)
**Author:** [@Draco\_Houston](https://forums.unrealengine.com/u/Draco_Houston)\ **Replies:** 7\ **Last updated:** [March 12, 2021, 4:11pm UTC](https://forums.unrealengine.com/t/binding-a-multicast-dynamic-delegate-via-blueprintnativeevent-from-a-blueprintable-native-interface/480102 "2021-03-12T16:11:37Z")
I am making an interface, blueprintable with BlueprintNativeEvent methods. For most purposes this has worked just fine, but I have run into a problem with exposing all the functionality I want via these interfaces. As is… --- ## [TSharedRef for interface](https://forums.unrealengine.com/t/tsharedref-for-interface/474068)
**Author:** [@Bionic\_Ape](https://forums.unrealengine.com/u/Bionic_Ape)\ **Replies:** 0\ **Last updated:** [November 5, 2020, 11:19pm UTC](https://forums.unrealengine.com/t/tsharedref-for-interface/474068 "2020-11-05T23:19:00Z")
I want to have a TMap of interfaces, but I want them to be garbage collected when nobody is referencing them. If I use TMap\\> it can be garbage collected, but TSharedRef can’t be an interface. … --- ## [Is there a way I can have publicly accessible object references?](https://forums.unrealengine.com/t/is-there-a-way-i-can-have-publicly-accessible-object-references/469749)
**Author:** [@ExpStealer](https://forums.unrealengine.com/u/ExpStealer)\ **Replies:** 5\ **Last updated:** [August 14, 2020, 3:18pm UTC](https://forums.unrealengine.com/t/is-there-a-way-i-can-have-publicly-accessible-object-references/469749 "2020-08-14T15:18:43Z")
I’ve been banging my head for the last couple hours now and can’t seem to find anything. It’s simple… Or at least it should be. I want to be able to communicate via interfaces to my HUD widgets, but I don’t want to have… --- ## [c++ interface not forcing implementation](https://forums.unrealengine.com/t/c-interface-not-forcing-implementation/468188)
**Author:** [@anonymous\_user\_98920181](https://forums.unrealengine.com/u/anonymous_user_98920181)\ **Replies:** 2\ **Last updated:** [July 15, 2020, 9:31am UTC](https://forums.unrealengine.com/t/c-interface-not-forcing-implementation/468188 "2020-07-15T09:31:00Z")
So I created a grabbable object interface with a simple function named grab in it. I then created an actor class that included the header for my Grabbable interface, then inherited from IGrabbable in my actor class. I sw… --- ## [Code design issue using interfaces to interact with objects](https://forums.unrealengine.com/t/code-design-issue-using-interfaces-to-interact-with-objects/464391)
**Author:** [@Xeru98](https://forums.unrealengine.com/u/Xeru98)\ **Replies:** 0\ **Last updated:** [April 28, 2020, 6:37pm UTC](https://forums.unrealengine.com/t/code-design-issue-using-interfaces-to-interact-with-objects/464391 "2020-04-28T18:37:12Z")
I’m working on a project where the user will have the ability to modify different properties on server owned objects. The current plan is to have all objects that can be interacted with implement some sort of interface t… --- ## [How to add default functions to c++ interface](https://forums.unrealengine.com/t/how-to-add-default-functions-to-c-interface/461430)
**Author:** [@Blindopoly](https://forums.unrealengine.com/u/Blindopoly)\ **Replies:** 5\ **Last updated:** [February 7, 2020, 11:59am UTC](https://forums.unrealengine.com/t/how-to-add-default-functions-to-c-interface/461430 "2020-02-07T11:59:03Z")
Hi, I’m wondering how I could add default functionality to a C++ interface. For example, I have created this interface (header) class My\_API IInteractableInterface { GENERATED\_BODY() // Add interface functions to th… --- ## [Blueprint interface doesn't seem to work.](https://forums.unrealengine.com/t/blueprint-interface-doesnt-seem-to-work/311317)
**Author:** [@anonymous\_user\_06824164](https://forums.unrealengine.com/u/anonymous_user_06824164)\ **Replies:** 21\ **Last updated:** [October 12, 2019, 8:44pm UTC](https://forums.unrealengine.com/t/blueprint-interface-doesnt-seem-to-work/311317 "2019-10-12T20:44:17Z")
First Actor http://puu.sh/gDCi4/9a2ec411f6.png Second Actor http://puu.sh/gDCj9/984404fa50.jpg I am trying to Print the boolean’s value set by the second actor from the first actor using a blueprint interface. Both a… --- ## [Are interface calls thread safe](https://forums.unrealengine.com/t/are-interface-calls-thread-safe/427082)
**Author:** [@anonymous\_user\_ff0ebfa4](https://forums.unrealengine.com/u/anonymous_user_ff0ebfa4)\ **Replies:** 4\ **Last updated:** [August 21, 2019, 11:33am UTC](https://forums.unrealengine.com/t/are-interface-calls-thread-safe/427082 "2019-08-21T11:33:33Z")
Dear community, I have a strange problem with interfaces. My async task does some interface calls in loop via Execute\_… method. And at that moment when GC starts, next call throws assertion !IsUnreachable() on calling o… --- ## [Creating a Dynamic Scroll Box](https://forums.unrealengine.com/t/creating-a-dynamic-scroll-box/451884)
**Author:** [@TannerIsBender](https://forums.unrealengine.com/u/TannerIsBender)\ **Replies:** 0\ **Last updated:** [July 8, 2019, 1:40pm UTC](https://forums.unrealengine.com/t/creating-a-dynamic-scroll-box/451884 "2019-07-08T13:40:51Z")
I’m extremely new to blueprint scripting and UE4, but I will not let it stop me from accomplishing my task! Please help, I’ve been stuck on this for a few days. I’ve tried following different tutorials, but they seem to … --- ## [C++ Interface: "Member Declation not allowed here".](https://forums.unrealengine.com/t/c-interface-member-declation-not-allowed-here/302207)
**Author:** [@Jambax](https://forums.unrealengine.com/u/Jambax)\ **Replies:** 6\ **Last updated:** [May 14, 2019, 10:09pm UTC](https://forums.unrealengine.com/t/c-interface-member-declation-not-allowed-here/302207 "2019-05-14T22:09:02Z")
I would like all of my instanced classes that feature the ‘IBZGame\_GameObjectInterface’ Interface, to have a UPROPERTY Struct that I can edit in all of the blueprints that I make of those classes. So for example, my str… --- ## [Declare, implement and call an interface in C++](https://forums.unrealengine.com/t/declare-implement-and-call-an-interface-in-c/366038)
**Author:** [@anonymous\_user\_213579db](https://forums.unrealengine.com/u/anonymous_user_213579db)\ **Replies:** 12\ **Last updated:** [April 29, 2019, 5:35pm UTC](https://forums.unrealengine.com/t/declare-implement-and-call-an-interface-in-c/366038 "2019-04-29T17:35:49Z")
I have an interface declared and called in C++. There are implementations in C++ and blueprints. I am following the documentation (Interfaces in Unreal Engine | Unreal Engine 5.2 Documentation), which doesn’t have an es… --- ## [How can I call a c++ interface function in Blueprint?](https://forums.unrealengine.com/t/how-can-i-call-a-c-interface-function-in-blueprint/430188)
**Author:** [@Sam54123](https://forums.unrealengine.com/u/Sam54123)\ **Replies:** 6\ **Last updated:** [November 9, 2018, 10:17am UTC](https://forums.unrealengine.com/t/how-can-i-call-a-c-interface-function-in-blueprint/430188 "2018-11-09T10:17:51Z")
Hello Sam54123, I do not really understand what the issue you are trying to solve. What is stopping you from make some simpler pieces of virtual equipment in Blueprint with BueprintCallable functions? As i understa… --- ## [I have a couple questions about best c++ practices:](https://forums.unrealengine.com/t/i-have-a-couple-questions-about-best-c-practices/435710)
**Author:** [@Sam54123](https://forums.unrealengine.com/u/Sam54123)\ **Replies:** 3\ **Last updated:** [October 16, 2018, 4:46am UTC](https://forums.unrealengine.com/t/i-have-a-couple-questions-about-best-c-practices/435710 "2018-10-16T04:46:17Z")
I’m having trouble getting help on the discord server because of my time zone, so here’s a couple questions regarding c++: If I’m trying to store and pass around an object that I know implements an interface, but I d… --- ## [Interface blueprints that run identical code with different outputs](https://forums.unrealengine.com/t/interface-blueprints-that-run-identical-code-with-different-outputs/426988)
**Author:** [@vycanis1801](https://forums.unrealengine.com/u/vycanis1801)\ **Replies:** 7\ **Last updated:** [September 11, 2018, 2:17am UTC](https://forums.unrealengine.com/t/interface-blueprints-that-run-identical-code-with-different-outputs/426988 "2018-09-11T02:17:33Z")
I have an interface blueprint called InteractInterface\_BP. I have a lot of different kind of actors that share a particular function, and its displaying text in my hud widget after the interaction occurs. For example, if… --- ## [Can't add interface to Blueprint](https://forums.unrealengine.com/t/cant-add-interface-to-blueprint/312729)
**Author:** [@anonymous\_user\_276962d7](https://forums.unrealengine.com/u/anonymous_user_276962d7)\ **Replies:** 8\ **Last updated:** [May 28, 2018, 12:33am UTC](https://forums.unrealengine.com/t/cant-add-interface-to-blueprint/312729 "2018-05-28T00:33:19Z")
After I had deleted my interface from a blueprintclass, I can’t add it again. interface is still visible in “Add interface window” but when click it, nothing happens. Does anyone have an idea how I can fix that? --- ## [\[Feature Request\] Blueprint "Get All Actors With Interface" Performance Improvement](https://forums.unrealengine.com/t/feature-request-blueprint-get-all-actors-with-interface-performance-improvement/389702)
**Author:** [@Jake1337](https://forums.unrealengine.com/u/Jake1337)\ **Replies:** 6\ **Last updated:** [May 16, 2018, 5:38pm UTC](https://forums.unrealengine.com/t/feature-request-blueprint-get-all-actors-with-interface-performance-improvement/389702 "2018-05-16T17:38:16Z")
Thanks in advance for anyone taking the time to ready this feature request, I hope more developers out there can resonate with this request and vote it up so it can be addressed soon. Background on our use case So we’v… [Next page](https://forums.unrealengine.com/tag/interfaces/4367.md?match_all_tags=true&page=1&tags%5B%5D=interfaces)