thevittfile

The plugin looks up the sub-attributes in your product, then for each value it looks up its parent and adds the parent attribute and the parent value in the product. 
When using a filter with the main attribute on the store page, all the products that have that main attribute are returned, which are the same products that contain the associated sub-attributes.
Important: 
You can’t create multiple hierarchy levels, just one. 
Two diferent attributes cannot contain the same sub-attribute.
<h3>Documentation</h3>
<a href="https://github.com/vittfiles/vitt-attribute-hierarchy" rel="nofollow ugc">vitt attribute hierarcht for woocommerce</a>

Vitt Attribute Hierarchy for WooCommerce

This plugin works simulating a hierarchy for attributes and subattributes.

Kuuak

After setting up WooCommerce and defining product attributes, you can define the default attributes, as well as there order, to be automatically added to new product.
It will make the creation of new product more efficient and fast as you won’t need 
to add manually the attributes, and remembering the same order for each new product.
Tested with WooCommerce version 3.3.3
<h3>Contribute</h3>
Don’t hesitate to fork this plugin and submit pull requests in the <a href="https://github.com/Kuuak/woo-default-attributes" rel="nofollow ugc">github repo</a>.

Woo Default Attributes

Define default attributes to be automatically added in WooCommerce new product page.

Vitt Attribute Hierarchy for WooCommerce vs Woo Default Attributes