Custom fields in PDF

Hello,

To single.php i added custom fields, (made by toolset).

the code is below

<?php if( types_render_field('model') ): ?>
<h5 class="cena"><p>Model: <b><?php echo types_render_field("model"); ?></b></p></h5>	
<?php endif; ?>

I wonder, how to show this field in pdf file.
I was try few options, but its not showing.

Can you advice, how should looks code If I want add it to dkpdf-index.php ?

Thanks for advice