A Material Boundary is used in Slide to define sub-regions within the External Boundary, which have different material properties.
To add a Material Boundary to your model:
Select Add Material Boundary from the toolbar or the Boundaries menu.
Enter the vertices of the Material Boundary as described in Entering Coordinates.
When all vertices are entered, right-click and select Done, or press Enter with nothing in the prompt line.
After Material Boundaries are drawn, then you must use the Define Materials and Assign Properties options in order to define the various material properties and assign them to the correct regions of the model.
If your model consists of a single soil type with uniform material properties throughout, then Material Boundaries are not necessary.
In order to properly define a material zone, a Material Boundary in Slide MUST DEFINE A CLOSED REGION, by virtue of intersection with the External Boundary, and / or other Material Boundaries. A Material Boundary could also define a closed region on its own, by connecting the first and last vertices. A Material Boundary which does NOT define a closed region, will not define a zone of different material, as you will discover when you are assigning properties.
The External Boundary must exist before Material Boundaries can be added to a model.
Typically, a Material Boundary will be a single line segment dividing the model into sub-regions by virtue of intersection with the External Boundary. However, the definition of a Material Boundary in Slide is completely general – it can have any number of segments, can intersect any other boundaries (including other Material Boundaries), and can even be a closed boundary.