osition	= position.clone()
		position.x	+= (Math.random()-0.5)*0.3
		position.y	+= (Math.random()-0.5)*0.1
		position.z	+= (Math.random()-0.5)*0.3
		// init sprite material
		var material	= new THREE.SpriteMaterial({
			map			: texture,
			useScreenCoordinates	: false,
			color			: 0x666666
		})
		// init sprite
		var sprite	= new THREE.Sprite(material)
		sprite.rotation	= Math.random() * Math.PI*2
		sprite.position.copy(position)
		scene.add(sprite)

		var maxAge	= 1 + Math.random()*0.4
		// set velocity
	