catalog_attributes.xml

<?xml version="1.0"?>
<!--
/**
 * Refer to LICENSE.txt distributed with the Temando Shipping module for notice of license
 */
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Catalog:etc/catalog_attributes.xsd">
    <group name="quote_item">
        <attribute name="ts_dimensions_length"/>
        <attribute name="ts_dimensions_width"/>
        <attribute name="ts_dimensions_height"/>
    </group>
</config>