Filter type Material allows you relate materials. It means this filter type allows you assign Material items to other Materials.
Filter type Material have several targets:
- Relate materials
- Create unique filters for sub-materials
- Create custom custom filters
1. Relate materials
If you need relate materials you can use filter type Material.
Just for example in our simple project management application we will add extra Material – Contacts to store simple contacts details and relate them with projects.

Then in Project filters we will create extra filter Material:Contacts

This filter allows you assign contacts to projects.

You can related any top Materials or top Materials with sub-materials or sub-materials to other sub-materials from the same parent Material. Sub-materials from different parent Materials can’t be related.
2. Create unique filters for sub-materials
At the moment we can create sub-materials. So to create unique filter for sub-materials we just need to create extra sub-material and using filter type Material we can relate it to other sub-materials.
Just for example in our simple project management application we will create sub-material Version for Project Material and relate Versions with Tasks

Then we will create filter Material:Version for Tasks

In result when we create task we can assign version to task and each project can have unique versions list.

3. Create custom custom filters
If filter have to store addition information (not just only Name like usual filter has) then you can create Material to store filter information and use filter type Material to create custom filter for other Materials.