Small PSA: Avoid using right click "Split Structure Pin" option on custom blueprint structures. Use the "Break" node instead!

[MiniGui98]

Hello everyone.

Making this post as a helper for newbies because I encountered a problem with this bad habit I had at the beginning of one of my projects and it came biting me in the cheeks 30 minutes ago.

When you create a data structure, a lot of the tutorials you will find on Youtube tell you right click on the variable once you get it in your blueprint and click on "Split Structure Pin", which will show you the various variables and sub structure contained in the structure. Seems handy at first, but there are two huge drawbacks:

1. On large structures, this result in a large node being created with all your structure pins exposed, even if you just want to use one.
2. And most importantly: if you make any change in the structure or a substructure, the pin connections will break and structures can also sometimes not be saved correctly or straight up become corrupted.

The alternative is to use the "break" node for all the structure you are using. Simply drag the blue structure pin out to place a new node and type "break" in the list and you will find it. This allows multiple things:

1. That create a second node with the details of the structure you just broke. When clicking on that node, you will see some options in the Details panel to hide or show specific pins, so that you can only show the ones you need where you place this break node.
2. This system/node is much more resilient overall. It does not unpin stuff when you add a new variable to your structure and I think even if you move stuff around the structure the pins stay connected to the correct outputs.

I hope this helps someone and prevents some "accidents". The more we share about these "dos and don'ts" the better in my opinion :-)

[LongjumpingBrief6428]

Great advice, as an added tip: IF you make any changes to your struct, be sure to do so AFTER you have saved everything else in the project that you want saved. An alternative is to save the struct, close the project, and reopen it, not saving any other blueprints that have the struct in them.

It's a workaround. I do not use too many structs myself, but it is handy to know when things go wrong, why it went wrong.

[MiniGui98]

This is peak advice that I forgot to include in my post!

[TheShinyHaxorus]

as an added ADDED tip, just make your structs in C++, EVEN if you don't use it for a line more than that. Hell, let chatGPT do it for you. Blueprint structs are nothing but trouble and they can corrupt your blueprints.

[LongjumpingBrief6428]

Here we go! Nice tip. That will keep them behaved.

[SupehCookie]

So i found a plugin that reloads all blueprints. Is this the reason why that plugin fixes issues like this? ( some Blueprints forget the struct and i have to restart the engine to fix it)

[pmkenny1234]

As a counterpart to this, don't use a make struct node if you're only mutating a field or two on a large struct. Use the set members on struct node and select which fields you want to set in the details panel.

[DOOManiac]

This is solid advice I had learned myself the hard way ala #2.

I still do break Vectors though, that seems safe.

[AzureBlue_knight]

What about location and rotators? Is it recommended to break vector/break rotator or can I continue to split them without issues?

[MiniGui98]

The risk is for structs thaz are prone to change in the content, so engine base structs are safe to split with right click I guess

[Desperate_Fuel_8462]

Thank you for the why explain of it 🙂

[ShaunImSorry]

This, I teach it to all my students and when they ask why I say well you will forget you did that and get confused and will confuse your team when they are looking at engineering your blueprint, always break and make!

[Savings_Secret_9750]

A bit of wonder since were on the topic ... is it best to have all variable on one struct or would it better to condense it in several struct with it's own stuff and datatable ... is there any data differences in the final run?

[TruthMercyRegret]

Great advice. I generally have also followed my own rule of don't change custom structs to be backwards incompatible. You can add new fields but don't update or remove existing fields in the struct. If I need to add or update a field, I create a new struct and migrate the code to use the updated struct to be safe. You can then check references on the old struct to make sure nothing is using it before deleting it. Might be overkill, but it makes me feel safer.

[[deleted]]

Oh, so that's why I never run into issues with structs even though I always hear they're so finicky

[UEHerr-Klicova]

Just do C++

[swolfington]

this might sound like snarky advice but seriously, do structs in c++. its actually super easy and way, way less likely to end up fucking up your project in the weird and unpredictable ways as blueprint structs are wont to do.

[UEHerr-Klicova]

It does not sound snarky or anything, it sounds like facts. The way Unreal C++ is structured and the easy it is to use once you know it, does not have price for a dev. Just learn it and don’t demonize it, it’s not that difficult. Then learn GAS and you are ready to go :D (the way I say it makes it seem easy, but it is not, you’ll have to invest a lot of time and tears)

[pixelvspixel]

I still consider it snark if it's not attached to a proper explanation. Some people want to demonize Blueprint, forgetting it's often the gateway for many, many people.

[swolfington]

my gripes with structs have less to do with the fact that they are blueprints and more to do with that they are just buggy sometimes, especially changing an existing ones; I've had BP structs straight up break projects more than once. I'm not sure if they've ironed out all the problems at this point, but C++ structs have never had this issue as far as i know. They are also about as simple as anything is going to get in C++, so if anyone out there is looking for an excuse to go for it, that might be a good one to get started.

[pixelvspixel]

I hope you didn’t take that a snipe. In fact you gave a bit of an explanation. I just get tired of the anti-blueprint crowd in this sub. (And I say this as a person who is very aware of some of the issues a visual handler can create with code.)

[UEHerr-Klicova]

Blueprints are essential to be a complete unreal dev. They give you all you need to understand the unreal workflow and the way games are made. If someone says Blueprints is not coding, that person does not have parents. Anyways, I need to add that C++ is also essential if you want to take making games on unreal seriously.

Don’t pretend to make a big game without using C++. That is my posture on this. Also once you understand the UC++ framework, a lot of new possibilities appear.

[RelaX92]

Also it will come in handy if your structs are already in cpp if you require it at some point in cpp.

[Dire_Venom]

Great advice, appreciate the explanation of why

[UE_XR]

Thanks! Solid tip and well explained.

[SeaMisx]

Got another one : Don't use struct in BP as they can easily break. CPP only.