Overlapping Objects

Learning targets

• Attribute domain identifiers
• Overlap objects with different priority
• Assign the computational domain

Typically geometries for FEM computation are constructed by overlapping different geometrical objects in one layout. For each object a domain identifier is specified (DomainId, for assigning material properties, etc.).

When geometrical primitives with different domain identifiers overlap with each other, the Priority parameter decides which of the domain identifier will be attributed to the overlap region: The DomainId of the primitive with the highest Priority will be attributed to the overlap region.

A layout containing a computational domain with some partially overlapping objects looks like this:

Layout2D {
  Objects {
    Polygon {
      DomainId = 1
      Priority = ComputationalDomain
      ...
    }
    Circle {
      Name = "TopCircle"
      DomainId = 4
      Priority = 3
      ...
    }
    Circle {
      Name = "BottomCircle"
      DomainId = 4
      Priority = 1
      ...
    }
    Parallelogram {
      Name = "MyParallelogram"
      DomainId = 5
      Priority = 2
      ...
    }
  }
}

In this example, the object MyParallelogram has a larger priority than the BottomCircle and a smaller priority than the TopCircle. The specific value of Priority = ComputationalDomain specifies that domain has a smaller priority than all overlapping objects, however, all parts of objects outside of the boundaries of this object are cut off / clipped. In this case a part of the object MyParallelogram is clipped. The resulting geometry and mesh corresponds to the following figure: