Changing struct public parameters of a blueprint reset parameters of the object in the scene

Development Programming & Scripting Blueprint
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1

Hello,
I have created a blue print with an array of struct as parameter.
When i want to edit the struct to add new parameters, saving and compiling my blueprint reset all parameter of my BP object in the scene.

screenshot
before changing the struc

100398-struct-before.jpg
100398-struct-before.jpg1172×443 55.7 KB

after adding params to the struc and compiling the code.

100399-struct-after.jpg
100399-struct-after.jpg1165×433 59.7 KB

Repro Steps
1 create a struct with variable (structA)
2 create a new struct (structB) and add previous one (structA) as variable
3 create a blueprint and add array variable of structB
4 add in your level and change variable
5 add a variable in structB , recompile you blueprint…
6 check your blueprint in the scene parameters changed to default

2

Hi eddieplay,

  • Does this occur in a clean, blank project with no additional content or is it limited to one project?
  • Does this only occur when you create a struct within a struct? Are there any additional steps I need to take to reproduce this error on my end?
  • With your repro steps, do you mean that once you add a copy of the blueprint to the level, you add a new variable to struct and it resets the values? I’m a bit unclear as to what you are experiencing on your end.
3

Hi Adam,

Does this occur in a clean, blank
project with no additional content or
is it limited to one project?

I’m working on the third person sample.

Does this only occur when you create a
struct within a struct? Are there any
additional steps I need to take to
reproduce this error on my end?I/

After few test it also occur with a simple struct put it has to be an array of struct variable public.

With your repro steps, do you mean
that once you add a copy of the
blueprint to the level, you add a new
variable to struct and it resets the
values? I’m a bit unclear as to what
you are experiencing on your end.

Yes.
I’m adding the copy of blueprint to the level and set variables parameter to produce content (example spawn object randomly), then when I add a new parameter to my struct (example control rotation) when I recompile all the other parameter that I previously changed in the level are reset to default one.

It is a 100% repro if you are using an array of struct

regards,
Eddie.

4

Hi eddieplay,

While looking into this I found that we have a bug report in for something very similar to what you are seeing here. Can you look and confirm whether or not this is what you are seeing on your end?

5

Hi Adam,

Yes it is similar.
but in the test i run even a simple array of struct and the same bug happened.

6

More than likely they are caused by the same root error. I will make an internal note that the error occurs with a simple struct array. For updates, please check the public bug link provided above.

7

thanks, FYI look like the problem does not occur in the 4.11.2

8

Thank you for this information, I have left an internal note updating the bug report.