v2.sub( va[1] );
v2.sub( va[0] );
	public Vector getNormal( )	{		if ( normal == null )		{			if ( va == null || va.length < 3 )			{				return null;			}			// create vectors with first three points and returns cross products			Vector v1 = new Vector( va[1] );			v1.sub( va[0] );			Vector v2 = new Vector( va[2] );			v2.sub( va[1] );			normal = v1.crossProduct( v2 );		}		return normal;	}