IGES or STEP

If using IGES or STEP formats to export from the CAD package, save the assembly to a single file. Simcenter STAR-CCM+ can read this file and translate the surface. At inter-region boundaries, Simcenter STAR-CCM+ automatically detects surfaces that are within close proximity and attempts to merge them, resulting in a common boundary at the interface (note that this process is not always successful). It also provides the option for generating part curves. The boundaries can then be separated out to interface and non-interface groups and duplicate copies are made of the boundaries at the inter-region interface. New regions can then be created which have the same triangulation for the boundaries at the interface. A single mesh operation can be used to volume mesh the entire geometry, resulting in a conformal mesh at the inter-region boundary interface.

If you save the individual parts in the assembly as separate IGES or STEP files, then on importing them into Simcenter STAR-CCM+ (either at the same time or one after the other), you are given the choice of whether to create one region per body, one region per file (recommended) or one region for all files. Regardless of the choice that you make, individual regions often have dissimilar triangulation at the inter-region boundaries. Usually Simcenter STAR-CCM+ can resolve different inter-region boundary triangulation by using the edge zipper to match the perimeter nodes and then deleting one of the boundaries to allow the creation of a conformal interface. However, depending on the variation in perimeter node positioning, the edge zipping can fail, in which case, use a different mesh operation for each region, which results in a non-conformal volume mesh interface. For this reason, it is recommended that you use the first approach that is discussed above to simplify the meshing process and guarantee a successful conformal interface.