diff --git a/Models/ProjectConfigJson.cs b/Models/ProjectConfigJson.cs
index 9cb93d7..3b61e3a 100644
--- a/Models/ProjectConfigJson.cs
+++ b/Models/ProjectConfigJson.cs
@@ -39,6 +39,38 @@ internal class AssetDirectories
         public string EnvironmentMapDirectory { get; set; } = "$(workingSpace)/Assets/EnvironmentMaps";
     }
 
+    internal class SkyDefaults
+    {
+        [JsonPropertyName("mode")]
+        public string Mode { get; set; } = "atmosphere";
+
+        [JsonPropertyName("environmentMap")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+        public Guid? EnvironmentMap { get; set; }
+
+        [JsonPropertyName("environmentIntensity")]
+        public float EnvironmentIntensity { get; set; } = 1.0f;
+
+        [JsonPropertyName("environmentTint")]
+        public float[] EnvironmentTint { get; set; } = new[] { 1.0f, 1.0f, 1.0f, 1.0f };
+
+        [JsonPropertyName("environmentYawRadians")]
+        public float EnvironmentYawRadians { get; set; } = 0.0f;
+    }
+
+    internal class RenderingSettings
+    {
+        [JsonPropertyName("environment_lighting_quality")]
+        public string EnvironmentLightingQuality { get; set; } = "standard";
+
+        [JsonPropertyName("environment_lighting_budget_mb")]
+        public int EnvironmentLightingBudgetMb { get; set; } = 384;
+
+        // Preserve other rendering policies when a configuration is round-tripped.
+        [JsonExtensionData]
+        public Dictionary<string, JsonElement>? AdditionalProperties { get; set; }
+    }
+
     internal class ProjectConfigJson
     {
         [JsonPropertyName("projectName")]
@@ -60,6 +92,12 @@ internal class ProjectConfigJson
         [JsonPropertyName("sceneList")]
         public IList<Scene> Scenes { get; set; } = new List<Scene> { new Scene() };
 
+        [JsonPropertyName("skyDefaults")]
+        public SkyDefaults SkyDefaults { get; set; } = new();
+
+        [JsonPropertyName("rendering")]
+        public RenderingSettings Rendering { get; set; } = new();
+
         public string ToJson() => JsonSerializer.Serialize(this, new JsonSerializerOptions { WriteIndented = true });
     }
 }
diff --git a/README.md b/README.md
index f130542..f00ff1e 100644
--- a/README.md
+++ b/README.md
@@ -80,6 +80,8 @@ See [Contributing.md](Contributing.md) for commit conventions, branch rules, and
 
 For local development with a custom engine build, see [docs/local-engine-path.md](docs/local-engine-path.md).
 
+For generated sky defaults and environment-lighting settings, see [docs/project-configuration.md](docs/project-configuration.md).
+
 ---
 
 ## License
diff --git a/docs/project-configuration.md b/docs/project-configuration.md
new file mode 100644
index 0000000..3c97251
--- /dev/null
+++ b/docs/project-configuration.md
@@ -0,0 +1,60 @@
+# Project configuration
+
+Panzerfaust writes `projectConfig.json` when creating a project. This is the
+project configuration passed to Obelisk; engine documentation and issue reports
+may also call this file `project.json`.
+
+New projects include these defaults alongside their asset directories and scenes:
+
+```json
+{
+  "skyDefaults": {
+    "mode": "atmosphere",
+    "environmentIntensity": 1,
+    "environmentTint": [1, 1, 1, 1],
+    "environmentYawRadians": 0
+  },
+  "rendering": {
+    "environment_lighting_quality": "standard",
+    "environment_lighting_budget_mb": 384
+  }
+}
+```
+
+## Sky defaults
+
+`skyDefaults` supplies authoring defaults for newly created or reset scenes.
+Saved scenes retain their own `SkyConfig`. Supported modes are `atmosphere`,
+`hdri`, and `skySphere`. The generated atmosphere uses the engine's default
+atmosphere settings.
+
+Environment intensity is a nonnegative multiplier. Tint contains four
+nonnegative RGBA components; white preserves the original colors. Yaw is a
+rotation in radians. The generated values match the engine's validated defaults.
+
+`environmentMap` is optional and omitted by default. When configuring an HDRI,
+set it to the imported environment asset's UUID string, rather than a file path.
+Generated IBL cache paths, renderer handles, and viewport state do not belong in
+this section.
+
+## Environment lighting
+
+`rendering.environment_lighting_quality` controls environment-lighting bake
+quality. The accepted tiers are:
+
+| Tier | Intended use |
+|---|---|
+| `low` | Lower-cost previews or constrained hardware; smaller lighting maps and fewer samples. |
+| `standard` | Default balance between lighting quality and bake cost. |
+| `high` | Higher-quality lighting with larger maps and more samples. |
+
+`rendering.environment_lighting_budget_mb` is a positive integer number of MiB.
+The default is `384`. It caps persistent environment textures, independently of
+the quality tier; it is neither a CPU memory budget nor a total GPU memory limit.
+
+Existing projects require no migration. Missing or invalid lighting settings
+fall back to `standard` and `384` in the engine. The editor also accepts the
+legacy `sky` section. Panzerfaust creates only new project configurations and
+does not rewrite existing configurations to add these defaults. Renaming a
+project preserves its other configuration properties, including rendering
+settings and legacy sky data.