Import step assembly with its compound

Feature Requests
1

Hi,

I would like to share a thought: it might make sense, if pmx automatically creates compounds if they exist in the native step file.

In the following example created for this post:

  • coumponds were made in freecad (volume were split)
  • if the step is imported into pmx, we can (only) see elementary volume (see fig)
  • if the same step is imported into gmsh and meshed, one can notice each compond corresponds to 1 physical tag (see the latest figs)
  • (does the pmx import module is based on gmsh kernel?)
  • the zip file contains the freecad files, the step one and the gmsh ones

This feature will be usefull for assemblies espacially if we’re dealing with dozens of elementary volumes.

The discussion remains open :grinning_face_with_smiling_eyes:

Paul

Assembly.zip (1.3 MB)

pmx
pmx1668×860 54.5 KB

gmsh_occ
gmsh_occ1241×778 35.8 KB

gmsh_PhysicalTag1
gmsh_PhysicalTag11233×777 55.5 KB

gmsh_PhysicalTag2
gmsh_PhysicalTag21237×780 40.2 KB

gmsh_PhysicalTag3
gmsh_PhysicalTag31237×777 36 KB

,

2

PrePoMax uses OpenCASCADE to handle geometry.

IMO such feature should be optional because you don’t always want compounds. Abaqus does it this way:

import step
import step330×383 6.97 KB

Personally, I would prefer an option to export multiple parts from PrePoMax to one .step file instead of generating a single file for each part.

3

Why not indeed; In my mind compounds are usefull if you have several parts and dozens (or more) of volume: it becomes easy to identify which volume belongs to which part (amonf other things)

4

You may e.g. want to mesh the parts with other hex meshing techniques that don’t support compounds (unlike transfinite mesh). Also, compound creation may fail in some cases: Deformation in 2 or more bodies - #10 by Matej

But it would just need a setting in Tools → Settings like other import options.

5

I also think this would be a nice feature :slight_smile:

6

How does this model looks in FreeCAD? Does it have only 3 bodies?

7

I used “A2plus” (assembly) workbench to perform the assembly; in the zip file all the native freecad files have been inserted

freecad1
freecad11340×546 41.9 KB

freecad2
freecad21165×602 37.7 KB

8

you’re right, but you can decide on your own to remove the compound if you want (volumes have been saved anyway); once again, if you’re working on an assembly:

  • such compounds will easy to identify which volume belongs to which part
  • with a huge amount of voulmes, it becomes difficult to dig into the volumes and you’ve to manually rename it (typically to create Elsets afterward)

my opinion … :grinning_face_with_smiling_eyes: