11 — JSON Presets

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JSON lets you store a system outside the binary Data Asset, review changes to the system in version control, generate presets with tools, and move them between projects.

Data Asset → JSON

Open a UFuzzySystemAsset and click Save To JSON. The editor:

1. compiles and validates the current system;
2. shows errors and doesn't write an invalid document;
3. opens the system save dialog;
4. appends .json if no extension was given;
5. writes a canonical document with SchemaVersion.

JSON → Data Asset

Click Load Preset and choose a .json file. Loading happens into a temporary structure. If the syntax, schema, or rules are invalid, the open Data Asset isn't changed. After success, the editor:

• replaces the system;
• refreshes Details, Variables, Inference, and Compile Log;
• marks the package as modified;
• creates an Undo transaction.

The path to an external JSON file is editor state, not a runtime property of the Data Asset. A packaged game uses the asset and doesn't depend on the loose file.

Blueprint API

Node	Parameters
Save Fuzzy System To Json	System, Content Relative Path, out Error
Load Fuzzy System From Json	Content Relative Path, out System, out Error

Blueprint paths are given relative to the Content directory, e.g. FuzzySystems/Driving.json. Attempting to escape Content via .. is rejected. The plugin's built-in presets are available via their full mount path, e.g. /FuzzyLogic/Demo/FuzzyDroneArena/DroneBehavior.json.

C++ API

#include "Serialization/FuzzySystemJson.h"

FString Json;
FText Error;
FFuzzySystemJson::ToJsonString(System, Json, Error);
FFuzzySystemJson::FromJsonString(Json, System, Error);

FFuzzySystemJson::SaveToFile(System, AbsolutePath, Error);
FFuzzySystemJson::LoadFromFile(AbsolutePath, System, Error);

FString Absolute;
FFuzzySystemJson::ResolveProjectRelativePath(
    TEXT("FuzzySystems/Driving.json"), Absolute, Error);

Every operation returns a bool; OutError explains a failure.

Schema 2

{
  "SchemaVersion": 2,
  "Settings": {
    "AndOperator": "Minimum",
    "OrOperator": "Maximum",
    "Implication": "Clip",
    "Aggregation": "Maximum",
    "DefuzzificationMethod": "Centroid",
    "SampleCount": 201
  },
  "Inputs": [
    {
      "Name": "Distance",
      "Range": { "Min": 0, "Max": 2000 },
      "DefaultValue": 1000,
      "Sets": [
        {
          "Name": "Near",
          "Function": {
            "Type": "Trapezoid",
            "LeftFoot": 0,
            "LeftShoulder": 0,
            "RightShoulder": 300,
            "RightFoot": 700
          }
        }
      ]
    }
  ],
  "Outputs": [
    {
      "Name": "Aggression",
      "Range": { "Min": 0, "Max": 1 },
      "Sets": [
        {
          "Name": "Bold",
          "Function": { "Type": "Triangle", "Left": 0.4, "Peak": 1, "Right": 1 }
        }
      ]
    }
  ],
  "Rules": [
    "IF Distance IS Near THEN Aggression IS Bold"
  ]
}

Fields

• SchemaVersion — the format version. A document with a newer, unknown version is rejected.
• Settings — all math settings; missing fields get default values.
• Inputs, Outputs — arrays of variables.
• Name and Range — required for a variable.
• DefaultValue — defaults to 0.
• Sets — an array of sets with Name and Function.
• Rules — an array of authored rule text.

Function.Type accepts Triangle, Trapezoid, Gaussian, Bell, Sigmoid, Ramp, JShape, Singleton, Constant, or a registered custom type. Every shape supports "Inverted": true.

An unknown type, or corrupted or truncated JSON, ends with a clean error without crashing the editor.