code: function calculatePositionOnCurve( u, p, q, radius, position ) {
  
  		var cu = Math.cos( u );
  		var su = Math.sin( u );
  		var quOverP = q / p * u;
  		var cs = Math.cos( quOverP );
  
  		position.x = radius * ( 2 + cs ) * 0.5 * cu;
  		position.y = radius * ( 2 + cs ) * su * 0.5;
  		position.z = radius * Math.sin( quOverP ) * 0.5;
  
  	}
docs: this function calculates the current position on the torus curve