Render the content of default_filter.php in Joomla front-end
PHP Snippet 1:
echo LayoutHelper::render('default_filter', array('view' => $this), JPATH_ROOT . '/components/com_mycomponent/tmpl/supportcases/');
echo LayoutHelper::render('default_filter', array('view' => $this), JPATH_ROOT . '/components/com_mycomponent/tmpl/supportcases/');