Discussion Forum

Hi

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

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Good luck
Ivar

Hi Ivar,

Thanks so much for ur suggestion. I did get the data from an imaging device: Fourier profilometry. Based on ur response, I suppose I can't create a mesh with these set of points with COMSOL. But you did mention other software allows you to create a mesh from a set of discrete points. Could you tell me what are some of those software..

At this point, I am guessing I could create a mesh out of these node points using NASTRAN. Is this right?

Please let me know when you get a chance..

Thanks again.

Arefin

Hi

no I do not believe NASTRAN is any better, it's just that they have a more or less public "neutral" file format used by certain to exchange mesh data. There are some other threads about mesh free-form conversion issues, try a search on the forum.
As this is not my field I do not have the names of the other software, they were present at the conferences in Paris, and certainly they are mentionned on the main web site too, but I do not know where

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Good luck
Ivar

Hi,

Would it be possible to fit a 3D surface on a point cloud in COMSOL. If it is possible , please let me know.

Thanks again for your last response..

Sincerely.

Arefin

Hi

I have bnever tried something like that, I would expect that there are far better tools out there, probably commercial though, have a look at:

www.comsol.eu/partners/

I beleive the your geometrical solution is provided by one of those

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Good luck
Ivar