To use TriangleLink, it must first be loaded:

Start by specifying the coordinates and displaying them:

Then create the input instance and set the points:

Next, the list of segments is created:

Set the segments in the input instance of Triangle:

This sets up variables that specify a point within a material domain, as well as a region attribute and a region constraint:

The material variables are set in the Triangle instance:

Retrieve the region values in a Triangle instance: