void centerAt() throws ScriptException {
		if (statementLength < 2)
			badArgumentCount();
		String relativeTo = null;
		switch (statement[1].tok) {
		case Token.absolute:
			relativeTo = "absolute";
			break;
		case Token.average:
			relativeTo = "average";
			break;
		case Token.boundbox:
			relativeTo = "boundbox";
			break;
		default:
			unrecognizedSubcommand(statement[1].toString());
		}
		Point3f pt = new Point3f(0, 0, 0);
		if (statementLength == 5) {
			// centerAt xxx x y z
			pt.x = floatParameter(2);
			pt.y = floatParameter(3);
			pt.z = floatParameter(4);
		}
		else if (statement[2].tok == Token.leftbrace) {
			pt = getCoordinate(2, true);
		}
		viewer.setCenter(relativeTo, pt);
	}