GMSH: Access extruded physical geometry
 

Hello there,

We are trying to simulate a statical calculation model which is a slab provided with lines and points that will be of interest later (e.g. for applying loads and springs in the statical model). We design the geometry as 2D and plan to use the extrude command for the volume generation.

A sample geometry can be found attached, this 2D model contains all relevant points and lines that we will have to access later as physical geometries. Additionally, not only the bottom surfaces, lines and points are of interest but also their counterpart at the top surface.

This is only a sample, the actual use cases will vary and will be created dynamically, thus we cannot rely on any tag numbers. We'd like to understand how we can extrude the 2D model into 3D without losing the physical group information and also create new physical groups for the extruded parts.

We tried many approaches, inkluding:

• Extrude lines, surfaces and points individually and assign the result to a new physical group (of the appropriate dimension) => Looks good in GMSH geometry but meshing fails with "extruded points cannot be found".
• Use OpenCASCADE factory and BooleanFragments / BooleanIntersection in a vast variety of ways in order to include our wanted geometries after extrusion => Whatever we try (applying the relevant geometries before or after extrusion, delete or keep tools or objects at booleanfragments, etc.), either the Physical Groups get deleted or don't play a role in the mesh / cannot be meshed.

We are happy to provide any of our examples so far, however, we have a feeling this might not be too relevant before we fully understand what is the best approach to solve our need.

We are more than happy to find any help here, may it be hints or ideas where to check, or also someone could spend the time looking at our example and get back to use.

Any help is much appreciated!

https://www.cfd-online.com/Forums/at...1&d=1604937298