Adding qty and add-to-cart in related products on product detail page for virtuemart 3 and display in linear fashion

php joomla e-commerce joomla3.0 virtuemart

If you are using overrides and you have

/templates/{your_template_folder}/html/com_virtuemart/sublayouts/addtocart.php

than you can use it in specific php overrides, in you specific php override

echo shopFunctionsF::renderVmSubLayout('addtocart',array('product'=>$this->product));

On how to use sub layout here official documentation

And also i think you need to read this one also CODE ADJUSTMENTS FOR VIRTUEMART 3

CodeHunter