In some cases parts or independent part instances contain details such as very small faces and edges. The Virtual Topology toolset allows you to remove these small details by combining a small face with an adjacent face or by combining a small edge with an adjacent edge. You can also ignore selected edges and vertices, which has the same effect as combining faces and edges. Introducing virtual topology is a convenient method for creating a clean, well-formed mesh. The Virtual Topology toolset is available only in the Mesh module.
You can mesh a wireframe part instance containing virtual topology; however, other part instances containing virtual topology can be meshed only under the following conditions:
You are using the free meshing technique to create triangular elements.
You are using the free meshing technique to create tetrahedral elements.
You are using the free meshing technique to create quadrilateral or quadrilateral-dominated elements using the advancing front algorithm.
In addition, you can apply virtual topology only to independent instances. If you need to apply virtual topology to a dependent instance, you can create a copy of the original part and then create an independent instance of the copy. You can then replace the dependent instance with the new independent instance and apply virtual topology to the independent instance. For more information, see What is the difference between a dependent and an independent part instance?, Section 13.3.2.