Geometry editing feature in Pre-processing

Feature Requests
1

Is there any plan to introduce the creation and editing features in pre-processing (Ex. FEMAP or Ansys Mechanical)?

My understanding is that, as of now, geometry editing has to be done using CAD software like FreeCAD.

2

In the very far future, this might be added to PrePoMax. But this is not an easy task. It means building the CAD modeler from scratch. And how many of those do you know which are open-source?

3

I certainly agree, this is not an easy job.
Can we take something from FreeCAD maybe?

4

While simple operations on geometry (such as partitioning) could be useful, I also think that actual CAD geometry creation should be really low on the priority list since PrePoMax should focus on what it was made for and there are good alternatives. IMO copying features from FreeCAD (which uses the only so powerful open-source CAD kernel called Open Cascade, utilized also by Salome and some other projects) doesn’t make much sense - it would never be as advanced as that software anyway. But maybe in the future, as a joint effort, it would be possible to create a geometry exchange interface that would allow you to automatically update the model in PrePoMax once the shape is modified in FreeCAD. Perhaps even with some parametric studies. After all, that’s mainly why you may want CAD and CAE in a single environment.

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5

Gmsh library used capable in solid modeling, editing and meshing by scripting language, maybe this advancement is possible to implementing in the future versions of PrePoMax.

6

Yes, Gmsh gives the possibility to perform CAD operations on geometry, which was not so easily possible before (it could be done through Netgen, which also supports OpenCascade). But creating the user interface for all these features and taking care of the modeling history, rebuilding the model, creating the sketcher, and a sketch solver is a lot of work/time.

7

Just to be clear, I didn’t mean full-fledged CAD modeling.
If you look, for example, as of now, one needs to create a mid-surface in CAD software to use shell elements.

  • So the question here is, can we have a pre-processor where based on geometry PrePoMax extracts the mid-surface?
  • Further users can split-merge, remove, and add features to the imported surface/solid.
    I understand this requires a massive amount of work.
8

Mid-surface extraction would indeed be nice. In FreeCAD it’s completely manual now. You can use the Facebinder and then 3D Offset tools to do the extraction itself but then the tricky part is to connect the extracted surfaces properly (typically by extrusion of subshapebinders based on edges).

I know that Matej planned to have a look at the possibilities of implementing some partitioning (Adding a feature to split edges of geometry) and defeaturing tools (the latter are really powerful in FreeCAD though: STEP file Cleanup) in the future.

Creating new geometrical features (even simple ones) would be much more problematic. Especially since primitives are usually insufficient.

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9

i’m not aware of modeling history, only think by calling *.geo script which similar to import/open CAD or Mesh file successfully generates in GUI. But maybe i’m too simple, not in details at implementation and it’s modeling history relationship and complexity.