Creating a new elastic foundation or changing its properties is performed by "Elastic foundation" 
:
Add Elastic Foundation - used to add/change elastic foundation properties like Cz value on a predefined region
Delete Elastic Foundation - used to remove elastic foundation from a region
When combined with "Create region" 
in Structure View elastic foundation is applied as a region with a predefined Cz parameter.
Elastic foundation properties are also displayed in "Plate definition" tree ("Elastic foundation" branch):
- Region – refers to the designed region of the plate containing a unique boundary condition set. Region itself is described in the lower branch(es) of the "Elastic foundation" tree;
- Label – refers to the unique boundary condition set of elastic foundation;
- Cz – elastic resistance value of the soil (kN/m2).
Right mouse click on selected "Elastic foundation" tree branch header allows to insert new elastic foundation region.
Lower level of main "Elastic foundation" tree branch is used to estimate/change coordinates for every vertex of elastic foundation region. Vertexes are sequentially listed it the table to define a polygonal contour of the Elastic foundation region.
The selected elastic foundation reference label in the "Elastic foundation" tree allows to remove elastic foundation objects with their boundary conditions through the context menu (right mouse click). The selected vertex(es) in the table allows to delete or insert new vertexes through the context menu (right mouse click).
Coordinates of vertex(es) are defined in the global coordinate system referenced to X=0 and Y=0 point.
Table of coordinates is supporting clipboard copy/paste functionality.