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Mesh Import

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Hello,

I have created a 2-d geometry and meshed it using an external meshing program. I can save these files as NASTRAN Bulk Data (.nas, .bdf, .nastran, .dat) but it seems that I can only import these into a 3-d model. I can save the file as .STL, .DXF, and VRML. If I do import the data in 3-d mode it won't let me select sub domains and such to get the problem setup. Is there something I am doing wrong?

MT

2 Replies Last Post 12.05.2010, 16:03 GMT-4

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Posted: 1 decade ago 12.05.2010, 10:38 GMT-4
For simplicity sake I have created a 2D .STL file and I have the ability to import it into COMSOL in 3D mode. The problem here is that when I want to assign a boundary condition it won't let me or if i want to extrude it wont let me do that either... how can i get past this situation. Furthermore how can I import (for example a .STL file) a mesh in 2-D mode??
For simplicity sake I have created a 2D .STL file and I have the ability to import it into COMSOL in 3D mode. The problem here is that when I want to assign a boundary condition it won't let me or if i want to extrude it wont let me do that either... how can i get past this situation. Furthermore how can I import (for example a .STL file) a mesh in 2-D mode??

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 12.05.2010, 16:03 GMT-4
Hi

I'm not sure it's possible like that, as in my understasnding the extrude or revolve can only be performed on geometries, and "mesh" are not "geometries" in Comsol's understanding.

But there is the function save mesh to assembled geometry, or to comsol geometry, which makes comsol attempt to recover the geometry, and then you might be able to adapt it.
If comsol manages to make an "assembled" geometry, you can attach boundary conditions (BC's) to it and perform a model solving "on" the imported mesh, if not you are introuble.

Personally, I only import true geometries and perform the "geomanalyse" and meshing in COMSOL.

The approach of COMSOL is somewhat different from other programmes, but far more logical in my view, it attaches BC to the geometries and then map of the geoemtries onto the relevant nodes and elements, this allows it to remesh far easier, as well as adapt the element discretizing, while in other programmes very often everything is attached to the mesh, if you remesh you redefine everything !

Have fun Comsoling
Ivar
Hi I'm not sure it's possible like that, as in my understasnding the extrude or revolve can only be performed on geometries, and "mesh" are not "geometries" in Comsol's understanding. But there is the function save mesh to assembled geometry, or to comsol geometry, which makes comsol attempt to recover the geometry, and then you might be able to adapt it. If comsol manages to make an "assembled" geometry, you can attach boundary conditions (BC's) to it and perform a model solving "on" the imported mesh, if not you are introuble. Personally, I only import true geometries and perform the "geomanalyse" and meshing in COMSOL. The approach of COMSOL is somewhat different from other programmes, but far more logical in my view, it attaches BC to the geometries and then map of the geoemtries onto the relevant nodes and elements, this allows it to remesh far easier, as well as adapt the element discretizing, while in other programmes very often everything is attached to the mesh, if you remesh you redefine everything ! Have fun Comsoling Ivar

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