4.7.6 - BP instance not updating


Following this thread: BP - Option to update instance - Feedback for Unreal Engine team - Unreal Engine Forums

Here a simple repro:

Create FPS C++ Template
Create a BP onto the ProjectNameCharacter class
Add the arms in First person mesh and third person mesh
Put the BP inside the level twice
Update the Character BP and clear the ThirdPersonMEsh, Save
you will see that the instanced BP are not updated with the changes.

As it should be the default behaviour to update all instance that are set to default value with the new ones, could you please fix this?

If it the expected behavior, could you please provide a way to propagate the changes? (like choosing the property to reset on all instance, or align all value that were equel to the previous default value).


Hi Elvince,

I wasn’t able to reproduce this in a new 4.7.6 project; clearing the third person mesh in the BP (derived from ProjectNameCharacter class) also removes it from instances in the level. This is, as Marc Audy stated in the forum thread you linked to, the way it’s supposed to work.

Have you altered source at all? Are there any additional steps you took that you might have left out? Did you see this occur in a new project? Any additional details could be helpful. Thanks!

I created a new project to repro this issue before creating this thread.

Just to be clear, when you said Clearing the mesh, you click on the little Yellow arrow icon or you delete the MeshComponent?
In my case, clearing, it’s clicking on the Yellow Arrow.

I will try again and see if I can share other information but my test was straightforward and fails from the first test.

Just to be sure, when you clear the mesh in the BP, it has automatically relfected the change in the Level view without any other command or manipulation?


Hey Elvince-

For clarification, opening the drop-down menu for the mesh and choosing the “Clear” option does update the instances in the viewport as well. I did notice that using the yellow arrow to “reset to defaults” does not have the same effect and does not update in the viewport. Additionally, this only seems to affect default components of the blueprint. Adding a new component (static/skeletal mesh) and setting a mesh to it will update in the viewport if the yellow arrow is pressed. This behavior has been bugged (UE-14627) for further investigation.


Doug Wilson

Thanks for the additional information.
This is an important features and that will be a time saver when this will work as intended.


it might worth to say that this issue may be also look for "standard "property (Like a float property) and not only mesh property.


2 years and 13 versions later and this is still broken.

I have a BP with TMap<> it doesn’t even get a yellow arrow to set to defaults. And it doesn’t update when you change the BP defaults. This seems like a major oversight.

Does epic typically just throw away all of their levels and re create them all whenever defaults change on their Blueprints? Because thats pretty much what epic is forcing us to do.

4.23 I have a blueprint that will not update no matter what but works properly only in NEW levels. It is preventing launch.

You need to recreate the broken levels that stores the reflected object data. Once a level is corrupted it cannot be repaired.

This happens a lot when programmers make incremental changes upon incremental changes but dont check them into source control. The small steps were ok, but to everyone else, (IE: the Build Process), the asset becomes broken.

I know its scary but not as bad as you think. I’ve done this a few times. Add a new empty level, and make it current. Highlight and move chunks of actors to the new level. Avoiding the broken instances. Saving / shelving frequently and testing. Then throw away the broken nearly empty level.

Sigh, thank you very much. Getting started now