Importing external meshes of arbitrary geometries

In the following some interesting questions and answers from COMSOL forum are collected here for a quick review.


Importing external meshes of arbitrary geometries

How to create a mesh from a .mph file containing a bunch of points?


COMSOL does NOT use meshes as “geometry”.
To be able to do multiphysics in a concise way COMSOL relies on:
1) geometrical Objects (your CAD model) and tranforms these into
2) Entities geoemtrical items called domains, boundaries , edges and points for a 3D model (see the doc)
3) Then you apply physics and boundary conditions on the domains and the boundary ENTITIES
4) you define also the shape functions on the entities, these define the number of intermediates nodes you will later use when analysing your elemetns (the methodoligy is subtily different from from traditional tools)
5) then you mesh and create elements and nodes, which heritate thei resective properties from the entities they are contained in or the boundaries they touch.
6) you solve with one or several of the numerous solvers
7) you postprocess an display your results

Therefore, those of you starting by importing a mesh and nodes you are trying to start in the middel: NO GOOD ! have first to get your mesh into step 1) by recombining it into a geoemtrical object.

Now, there is still a little hope (as always 😉 many of you receive meshed geometry from scan images or others, there are a few companies having specific software to transform such meshed geometries, but in 3.5a you can also import Nastran Neutral files Mesh definitions, then COMSOL v3.5a is rather good to create an analysed geoemtry therefrom. This can sometimes even be transformed into geometrical objects by COMSOL. It is worth a try (this functionality seems not yet as efficient in V4.1, hope it comes soon 😉 The 3.5 generated mphbin can then be read into v4 fo further processing from 1-7 as stated above.

Hope this helps

Good luck


Keeping track of subdomains/boundaries in 4.0a