Three-Way Interfaces in Combination with Morpher

This scenario includes two different approaches that are usually applied independently—Three-way Interface and Object Sliding on a Curved Surface.

Three-way Interface

A three-way interface is required usually when a Region A connects and disconnects with boundaries on Region B and Region C. In the following example Region A is an inlet/outlet pipe connected to an overset region and a background region:

Important Setups

Create a boundary interface from the contact surface between the inlet and overset regions, as well as a boundary interface between the inlet and background regions as illustrated below:

Depending on the current position of the overset region, the inflow through the inlet boundary is split between the overset and background regions. At a certain position, the inflow is disconnected from one region or both regions:

Object Sliding on a Curved Surface

To realize an object sliding along a curved surface, the boundaries in the moving region must be split into several boundaries with different Morphing Specifications.

Important Setups

• Interface Boundaries (grey): Constraint. The boundaries are enforced to slide on the cylindrical surface. You are advised to extract the outer surface of the background region and define it as a new part within the Geometry > Parts node.
• Upper Walls (blue): Displacement. You apply the trajectory motion Trajectory 1 > Constrained Rotation specified within the Tools > Motions node to these walls to achieve a described movement of the region.

  The trajectory path of the inlet region is shown below:

  
  

  

  
  
  
  

  

  
  

  As illustrated below, when defining a trajectory path, make sure that the start of the trajectory path is aligned with the point(s) of the geometry.

  To achieve sliding along a curved surface, you must define a constrained rotation, which rotates the other end of the inlet region such that the contact surface is always attached to the curved surface all the time.

  
  

  

  
  
  
  

  

  
  

  For another example of trajectory motion, see also: Paint Dipping: Defining the Trajectory Motion with Constrained Rotation.

• Lower Walls (green): Floating. When sliding on a curved surface, ensuring certain freedom of movement for the vertices stabilizes the morphing process.

For more details of the morphing specification, refer to Morpher Boundary Condition Reference.

In this example, the motions of the four regions are defined as follows:

Region	Motion Specification
Background	Stationary
Overset	User Defined Vertex
Inlet	Morphing
Outlet	Morphing

Further Steps

For the overset region, apply the Overset Topology: Bounded. This expert option helps the overset hole-cutting process when the overset region is bounded by a wall boundary of the background region. See also: Overset Topology: Bounded.

Trouble Shooting

• Enable close proximity.
• Enable alternate hole cutting.