function launchPopup (URL, w, h) {
	var chasm = screen.availWidth;
	var mount = screen.availHeight;
	if (!w) { w = 720; }
	if (!h) { h = Math.ceil(mount * 0.9); }

	var features =
		'width=' + w + 
		',height=' + h + 
		',left=' + ((chasm - w - 10) * .5) + 
		',top=' + ((mount - h - 150) * .5) +
		',scrollbars=yes';
			
	if (!new_window) 
	{
		var new_window = window.open (URL, 'Atelier', features);
		if (new_window) new_window.focus();
	}
}

function showRendering() {
	launchPopup('rendering.html');
}