diff --git a/source/Behavior/Brownian.ts b/source/Behavior/Brownian.ts
index 5f6293a..fab6cae 100644
--- a/source/Behavior/Brownian.ts
+++ b/source/Behavior/Brownian.ts
@@ -7,7 +7,9 @@ type IBrownianBehaviorParameter = {
     maxFrequency: "number",
 	minFrequency: "number",
 	maxStrength: "number",
-	minStrength: "number"
+	minStrength: "number",
+	dirLimit: "boolean",
+	angle: "number"
 }
 
 type IBrownianBehaviorEvent = {}
@@ -28,9 +30,88 @@ class Brownian extends Behavior<IBrownianBehaviorParameter, IBrownianBehaviorEve
 		maxFrequency: { type: "number", name: "$Max.Frequency", defaultValue: 5, numberStep: .1, numberMin: 0 },
 		minFrequency: { type: "number", name: "$Min.Frequency", defaultValue: 0, numberStep: .1, numberMin: 0 },
 		maxStrength: { type: "number", name: "$Max.Strength", defaultValue: 10, numberStep: .01, numberMin: 0 },
-		minStrength: { type: "number", name: "$Min.Strength", defaultValue: 0, numberStep: .01, numberMin: 0 }
+		minStrength: { type: "number", name: "$Min.Strength", defaultValue: 0, numberStep: .01, numberMin: 0 },
+		dirLimit: { type: "boolean", name: "$Direction.Limit", defaultValue: false },
+		angle: {
+			type: "number", name: "$Angle", defaultValue: 180, numberStep: 5,
+			numberMin: 0, numberMax: 360, condition: { key: "dirLimit", value: true }
+		}
 	};
 
+	private randomFocus360(): number[] {
+		let randomVec = [
+			Math.random() * 2 - 1,
+			Math.random() * 2 - 1,
+			Math.random() * 2 - 1
+		];
+
+		let randomVecLen = (randomVec[0] ** 2 + randomVec[1] ** 2 + randomVec[2] ** 2) ** 0.5;
+		return [randomVec[0] / randomVecLen, randomVec[1] / randomVecLen, randomVec[2] / randomVecLen];
+	}
+
+	private rotateWithVec(vec: number[], r: number[], ang: number) {
+
+		const cos = Math.cos(ang); const sin = Math.sin(ang);
+		const a1 = r[0] ?? 0; const a2 = r[1] ?? 0; const a3 = r[2] ?? 0; 
+
+		return [
+			(cos + (1 - cos) * a1 * a1) * (vec[0] ?? 0) +
+			((1 - cos) * a1 * a2 - sin * a3) * (vec[1] ?? 0) +
+			((1 - cos) * a1 * a3 + sin * a2) * (vec[2] ?? 0),
+
+			((1 - cos) * a1 * a2 + sin * a3) * (vec[0] ?? 0) +
+			(cos + (1 - cos) * a2 * a2) * (vec[1] ?? 0) +
+			((1 - cos) * a2 * a3 - sin * a1) * (vec[2] ?? 0),
+
+			((1 - cos) * a1 * a3 - sin * a2) * (vec[0] ?? 0) +
+			((1 - cos) * a2 * a3 + sin * a1) * (vec[1] ?? 0) +
+			(cos + (1 - cos) * a3 * a3) * (vec[2] ?? 0)
+		]
+	}
+	private angle2Vector(v1: number[], v2: number[]): number {
+		return Math.acos(
+			(v1[0] * v2[0] + v1[1] * v2[1] + v1[2] * v2[2]) /
+			(
+				(v1[0] ** 2 + v1[1] ** 2 + v1[2] ** 2) ** 0.5 *
+				(v2[0] ** 2 + v2[1] ** 2 + v2[2] ** 2) ** 0.5
+			)
+		) * 180 / Math.PI;
+	}
+
+	private randomFocusRange(dir: number[], angle: number): number[] {
+
+		// 计算 X-Z 投影
+		let pxz = [dir[0] ?? 0, 0, dir[2] ?? 0];
+
+		// 通过叉乘计算垂直向量
+		let dxz: number[];
+
+		// 如果投影向量没有长度，使用单位向量
+		if (pxz[0] ** 2 + pxz[2] ** 2 === 0) {
+			dxz = [0, 0, 1];
+		}
+
+		// 通过叉乘计算垂直轴线
+		else {
+			dxz = [
+				dir[1] * pxz[2] - pxz[1] * dir[2],
+				dir[2] * pxz[0] - pxz[2] * dir[0],
+				dir[0] * pxz[1] - pxz[0] * dir[1]
+			];
+
+			let lenDxz = (dxz[0] ** 2 + dxz[1] ** 2 + dxz[2] ** 2) ** 0.5;
+			dxz = [dxz[0] / lenDxz, dxz[1] / lenDxz, dxz[2] / lenDxz];
+		}
+
+		// 航偏角 360 随机旋转
+		let randomH = this.rotateWithVec(dxz, dir, Math.random() * Math.PI * 2);
+
+		// 俯仰角 180 * R 随机旋转
+		let randomP = this.rotateWithVec(dir, randomH, (Math.random() - 0.5) * 2 * angle * Math.PI / 180);
+		
+		return randomP;
+	}
+
 	public effect = (individual: Individual, group: Group, model: Model, t: number): void => {
 
 		const {maxFrequency, minFrequency, maxStrength, minStrength} = this.parameter;
@@ -41,11 +122,43 @@ class Brownian extends Behavior<IBrownianBehaviorParameter, IBrownianBehaviorEve
 		
 		currentTime += t;
 		if (currentTime > nextTime) {
+
+			let randomDir: number[];
+
+			// 开启角度限制
+			if (this.parameter.dirLimit) {
+
+				// 计算当前速度大小
+				const vLen = individual.vectorLength(individual.velocity);
+
+				// 随机旋转算法
+				if (vLen !== 0) {
+					randomDir = this.randomFocusRange(
+						[
+							individual.velocity[0] / vLen,
+							individual.velocity[1] / vLen,
+							individual.velocity[2] / vLen
+						],
+						this.parameter.angle / 2
+					);
+				}
+
+				else {
+					randomDir = this.randomFocus360()
+				}
+			}
+			
+			// 随机生成算法
+			else {
+				randomDir = this.randomFocus360()
+			}
+
 			individual.applyForce(
-				minStrength + (Math.random() * 2 - 1) * (maxStrength - minStrength),
-				minStrength + (Math.random() * 2 - 1) * (maxStrength - minStrength),
-				minStrength + (Math.random() * 2 - 1) * (maxStrength - minStrength)
+				minStrength + randomDir[0] * (maxStrength - minStrength),
+				minStrength + randomDir[1] * (maxStrength - minStrength),
+				minStrength + randomDir[2] * (maxStrength - minStrength)
 			);
+
 			nextTime = minFrequency +  Math.random() * (maxFrequency - minFrequency);
 			currentTime = 0;
 		}
@@ -78,7 +191,15 @@ class Brownian extends Behavior<IBrownianBehaviorParameter, IBrownianBehaviorEve
 		"$Min.Strength": {
             "ZH_CN": "最小强度",
             "EN_US": "Minimum strength"
-        }
+        },
+		"$Direction.Limit": {
+			"ZH_CN": "开启角度限制",
+            "EN_US": "Enable limit angle"
+		},
+		"$Angle": {
+			"ZH_CN": "限制立体角 (deg)",
+            "EN_US": "Restricted solid angle (deg)"
+		}
     };
 }