Clicking the Fill button in the Parts panel displays the following dialog in the lower region of the panel :
This dialog lets you fill the selected Part with materials and initial conditions.
The only option available for unstructured parts is to fill the whole part. When an unstructured parts only needs to be filled partially, the Group option can be used to create a selected group of elements which then can be filled with materials or initial conditions.
Fill by Index Space
Fill a block in index space.
Fill a plane in index space.
Fill a node.
Fill a block in index space with unused elements.
Fill a composite shell.
Fill Multiple Parts
Fill multiple Parts.
Additional Fill Options
Read or write a datafile for General Remapping.
Fill an Euler Part using Lagrange or Fill Parts.
Read or write a datafile for Fast Block Remapping.