get random points on mesh

RandomOnMesh.cs

using UnityEngine;
using System.Collections;

public class RandomOnMesh : MonoBehaviour {
	void OnDrawGizmos(){
		Gizmos.color = Color.red;
		for (int i = 0; i < 100; i++) {
			Gizmos.DrawSphere(
				GetRandomPointOnMesh(GetComponent<MeshFilter>().sharedMesh),
				0.1f
				);
		}
	}

	Vector3 GetRandomPointInTriangle(Vector3 v0, Vector3 v1, Vector3 v2){
		Vector3
			p1 = Vector3.Lerp (v0, v1, Mathf.Sqrt(Random.value)),
			p2 = Vector3.Lerp (v0, v2, Mathf.Sqrt(Random.value));
		return Vector3.Lerp (p1, p2, Random.value);
	}

	Vector3 GetRandomPointOnMesh(Mesh mesh){
		int rand = Random.Range(0, mesh.triangles.Length/3);
		Vector3[] triangle = new Vector3[3]{
			mesh.vertices[mesh.triangles[rand*3]],
			mesh.vertices[mesh.triangles[rand*3+1]],
			mesh.vertices[mesh.triangles[rand*3+2]]
		};
		return GetRandomPointInTriangle (triangle [0], triangle [1], triangle [2]);
	}
}