Here, note that I commented in the first while(1) loop. I also changed player to raincurtain, because this is the entity that generates the particles that is moving. I want the particles to follow this invisible entity, not the player.

I get no errors, but its not moving...

Code:

---

entity* raincurtain;

action cloud_object
{
	raincurtain = me;
	my.skill1 = 0;
	my.alpha = 98;
	my.transparent = on;
	//while(1)
	//{
		
	//MOVEMENT
	// NOTE: LAISSER LE CHIFFRE AVANT TIME_STEP PAREIL POUR TOUTES LES ACTIONS DE L'ORAGE.
	while(picked_angle == 0) { wait(1); } // wait until choose_way has run
	my.pan = picked_angle;
	while(1)
		{
			temp.x = 2*time_step; // change 5 to whatever speed you want
			temp.y = 0;
			temp.z = 0;
			c_move(me,temp,nullvector,null);
			wait(1);
		}
		
		// generate cloud particals once
		while (my.skill1 < ent_vertices(my)) // repeat till all vertices are passed
		{
			
			my.x = raincurtain.x;
			my.y = raincurtain.y;
			my.z = raincurtain.z;
			
			//clou();
			vec_for_vertex(temp.x,me,my.skill1);
			if (temp.z < my.z)
			{
				temp.z -= random(20); //temp.z -= random(20);
				temp.y += random(120)-60; //temp.y += random(120)-60;
				temp.x += random(20)-10; //temp.x += random(20)-10;
				effect(dark_cloud,1,temp,nullvector);	
			}
			if (temp.z < my.z-200)
			{
				temp.z += random(20);
				temp.y += random(120)-60; //temp.y += random(120)-60;
				temp.x += random(10)-5;
				effect(mid_cloud,1,temp,nullvector);	
			}
			if (temp.z > my.z)
			{
				temp.z += random(20);
				temp.y += random(120)-60; //temp.y += random(120)-60;
				temp.x += random(10)-5;
				effect(light_cloud,1,temp,nullvector);	
			}
			my.skill1 += 1;
		}
		//my.skill1 = 0;

	//	wait(1);
	//}
	
	

}

---