How change "Float Curve" key value?

[Belketh]

Hello.

Is it possible to change the Float Curve key value using Blueprint?
If not, is it even possible to programmatically change the value of the Float Curve key?

[Belketh]

I found a solution. I want to share it with you.
To do this, you need to create a custom node using C++.
If you do not use C++ in your project, then you need to download Visual Studio. You can read the instructions here: Setting Up Visual Studio Development Environment For C++ Projects In Unreal Engine | Unreal Engine 5.1 Documentation | Epic Developer Community
After installation:

1. Open your project - Tools - New C++ class

2. All classes - BlueprintFunctionLibrary - Next
   

   

3. Set the name of your library - Create Class
   

   

4. If VS does not open then go to your project folder and there should be a file [YourProjectName].sln. Open it.
   In Solution Explorer: Game - [YourProjectName] - Source - [YourProjectName] - Open [YourLibraryName].cpp and [YourLibraryName].h
   If VS opens then [YourLibraryName].cpp and [YourLibraryName].h will be open.

5. In [YourLibraryName].h paste code:

#pragma once

#include "CoreMinimal.h"
#include "Kismet/BlueprintFunctionLibrary.h"
#include "Curves/CurveFloat.h"
#include "[YourLibraryName].generated.h" /*Replace [YourLibraryName] with your library name*/

UCLASS()
class [YourProjectName]_API U[YourLibraryName] : public UBlueprintFunctionLibrary /*Replace [YourProjectName] with your project name in capital letters. Replace [YourLibraryName] with your library name*/
{
	GENERATED_BODY()

public:
	UFUNCTION(BlueprintCallable, Category = "My Custom Function")
	static void SetFloatCurveKeyValue(UCurveFloat* Curve, float Time, float NewValue);

};

6. In [YourLibraryName].cpp paste code:

#include "[YourLibraryName].h" /*Replace [YourLibraryName] with your library name*/

void U[YourLibraryName]::SetFloatCurveKeyValue(UCurveFloat* Curve, float Time, float NewValue) /*Replace [YourLibraryName] with your library name*/
{
    if (!Curve) return;

    // Find a key that matches a given time
    FKeyHandle KeyHandle = Curve->FloatCurve.FindKey(Time);

    // If the key is not found, add a new key
    if (KeyHandle == FKeyHandle::Invalid())
    {
        Curve->FloatCurve.AddKey(Time, NewValue);
    }
    else
    {
        //Changing the value of an existing key
        Curve->FloatCurve.UpdateOrAddKey(Time, NewValue);
    }
}

7. Save all
8. In Solution Explorer: Game - [YourProjectName] - Right click - Build
9. If everything went well, then you can find your node in the blueprint: