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Change space dimension from '2D' to 'Axial symmetry (2D)' without re-modelling the geometry

Posted 2011年1月14日 GMT-5 04:27 Geometry, Mesh 13 Replies

Sebastian Gatzka
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Hello World.

One of my fellow students modeled a rather complex geometry in Comsol 3.5 in a cartesian 2D geometry.
Unfortunately the space dimension should be solved in a cylindrical 2D dimension.

Changing the space dimension from '2D' to 'Axial symmetry (2D)' made no change to the model.
In the past I had to re-create the geometry to solve it in a different space dimension.
As the geometry is now rather complex I really would like to avoid re-creating it.

Is there a way to transfer the geometry from one space dimension to another?

Many thanks and hope to hear from you!
Sebastian
13 Replies Last Post 2016年11月15日 GMT-5 02:16
Edgar Kaiser
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Posted: 1 decade ago 2011年1月14日 GMT-5 05:58
Hi,

changing the symmetry does change the model. The way the cross section on your 2D workplane is translated into 3D is completely different.
In the 2D planar case the cross section is extruded along the axis perpendicular to your workplane. In axial symmetry the cross section is revolved around the z-axis.
What you see on the workplane remains the same, it is just a cross section.

Best regards
Edgar
Hi, changing the symmetry does change the model. The way the cross section on your 2D workplane is translated into 3D is completely different. In the 2D planar case the cross section is extruded along the axis perpendicular to your workplane. In axial symmetry the cross section is revolved around the z-axis. What you see on the workplane remains the same, it is just a cross section. Best regards Edgar
Sebastian Gatzka
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Posted: 1 decade ago 2011年1月14日 GMT-5 06:13

Hi,

changing the symmetry does change the model. The way the cross section on your 2D workplane is translated into 3D is completely different.
In the 2D planar case the cross section is extruded along the axis perpendicular to your workplane. In axial symmetry the cross section is revolved around the z-axis.
What you see on the workplane remains the same, it is just a cross section.

Best regards
Edgar


Hi Edgar.

Thanks for your reply.
I'm aware of the methods the cross section is treated inside the different coordinate systems.

But I'm not sure if you are implying with your answer that it's impossible to transfer the geometrical objects to another space dimension ?

Greetings.
Sebastian

[QUOTE] Hi, changing the symmetry does change the model. The way the cross section on your 2D workplane is translated into 3D is completely different. In the 2D planar case the cross section is extruded along the axis perpendicular to your workplane. In axial symmetry the cross section is revolved around the z-axis. What you see on the workplane remains the same, it is just a cross section. Best regards Edgar [/QUOTE] Hi Edgar. Thanks for your reply. I'm aware of the methods the cross section is treated inside the different coordinate systems. But I'm not sure if you are implying with your answer that it's impossible to transfer the geometrical objects to another space dimension ? Greetings. Sebastian
Edgar Kaiser
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Posted: 1 decade ago 2011年1月14日 GMT-5 06:46
Hi,

I probably don't understand what you actually mean. Maybe you can explain in more detail which kind of objects you are talking about.

Regards
Edgar
Hi, I probably don't understand what you actually mean. Maybe you can explain in more detail which kind of objects you are talking about. Regards Edgar
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 2011年1月14日 GMT-5 06:51
Hi

if you have a model in 2D (with nothing to the left of the axis (0,0,1) then you can save it as a mphbin, and reload it (as one block) in a 2D-axi.

You can even add or subtract new geoemtry to/from it.

But you still need to redefine fully the physics and BC's

--
Good luck
Ivar
Hi if you have a model in 2D (with nothing to the left of the axis (0,0,1) then you can save it as a mphbin, and reload it (as one block) in a 2D-axi. You can even add or subtract new geoemtry to/from it. But you still need to redefine fully the physics and BC's -- Good luck Ivar
Sebastian Gatzka
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Posted: 1 decade ago 2011年1月14日 GMT-5 11:08

Hi,

I probably don't understand what you actually mean. Maybe you can explain in more detail which kind of objects you are talking about.

Regards
Edgar


I have 14 rectangular geometry objects for which I want to change the space dimension from "2D" to "Axial symmetry (2D)"!

[QUOTE] Hi, I probably don't understand what you actually mean. Maybe you can explain in more detail which kind of objects you are talking about. Regards Edgar [/QUOTE] I have 14 rectangular geometry objects for which I want to change the space dimension from "2D" to "Axial symmetry (2D)"!
Sebastian Gatzka
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Posted: 1 decade ago 2011年1月14日 GMT-5 11:11

Hi

if you have a model in 2D (with nothing to the left of the axis (0,0,1) then you can save it as a mphbin, and reload it (as one block) in a 2D-axi.

You can even add or subtract new geoemtry to/from it.

But you still need to redefine fully the physics and BC's

--
Good luck
Ivar


How can this be done?
Exporting the geometry objects to a file is no problem, but how can they be imported into another model?
When choosing Import Geometry objects they need to be present in the Workspace?!

[QUOTE] Hi if you have a model in 2D (with nothing to the left of the axis (0,0,1) then you can save it as a mphbin, and reload it (as one block) in a 2D-axi. You can even add or subtract new geoemtry to/from it. But you still need to redefine fully the physics and BC's -- Good luck Ivar [/QUOTE] How can this be done? Exporting the geometry objects to a file is no problem, but how can they be imported into another model? When choosing Import Geometry objects they need to be present in the Workspace?!
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 2011年1月14日 GMT-5 15:43
Hi

I do not really understand wht you mean by:

"When choosing Import Geometry objects they need to be present in the Workspace?! "

But I must also admit that 3.5 (even 3.5a) is getting oldish for me, havent used it for a year or more, the v4 revolution has passed and been integrated, for me ;)

--
Good luck
Ivar
Hi I do not really understand wht you mean by: "When choosing Import Geometry objects they need to be present in the Workspace?! " But I must also admit that 3.5 (even 3.5a) is getting oldish for me, havent used it for a year or more, the v4 revolution has passed and been integrated, for me ;) -- Good luck Ivar
Sebastian Gatzka
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Posted: 1 decade ago 2011年1月15日 GMT-5 04:28

Hi

I do not really understand wht you mean by:

"When choosing Import Geometry objects they need to be present in the Workspace?! "

But I must also admit that 3.5 (even 3.5a) is getting oldish for me, havent used it for a year or more, the v4 revolution has passed and been integrated, for me ;)

--
Good luck
Ivar


Hi.

Maybe the attached file will illustrate the steps I tried to do.
Would you mind having a look?

Thanks, Sebastian

[QUOTE] Hi I do not really understand wht you mean by: "When choosing Import Geometry objects they need to be present in the Workspace?! " But I must also admit that 3.5 (even 3.5a) is getting oldish for me, havent used it for a year or more, the v4 revolution has passed and been integrated, for me ;) -- Good luck Ivar [/QUOTE] Hi. Maybe the attached file will illustrate the steps I tried to do. Would you mind having a look? Thanks, Sebastian

Attachments:

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 2011年1月15日 GMT-5 16:11
Hi

I have just tried to make a 2D model (in v3.5.0.608 =3.5a and v4.1.0.112), save it, and reload it in a new model defined as 2D-axi, I do the same sequence as in your pdf file, except the last step is not there, the geometry is appearing as expected !

could it be a version or a patch missing in your case ?

I noticed too, that in 3.5a I could define a 2D geometry and a given application mode, and then add a new application mode to the SAME geometry, but this one defined in 2D-axi. But I havent solved anything so I do not know how COSMOL treats 2D geometry defined as x,y for one application mode, and as r,z for another

--
Good luck
Ivar
Hi I have just tried to make a 2D model (in v3.5.0.608 =3.5a and v4.1.0.112), save it, and reload it in a new model defined as 2D-axi, I do the same sequence as in your pdf file, except the last step is not there, the geometry is appearing as expected ! could it be a version or a patch missing in your case ? I noticed too, that in 3.5a I could define a 2D geometry and a given application mode, and then add a new application mode to the SAME geometry, but this one defined in 2D-axi. But I havent solved anything so I do not know how COSMOL treats 2D geometry defined as x,y for one application mode, and as r,z for another -- Good luck Ivar
Sebastian Gatzka
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Posted: 1 decade ago 2011年1月16日 GMT-5 05:19

Hi

I have just tried to make a 2D model (in v3.5.0.608 =3.5a and v4.1.0.112), save it, and reload it in a new model defined as 2D-axi, I do the same sequence as in your pdf file, except the last step is not there, the geometry is appearing as expected !

could it be a version or a patch missing in your case ?

I noticed too, that in 3.5a I could define a 2D geometry and a given application mode, and then add a new application mode to the SAME geometry, but this one defined in 2D-axi. But I havent solved anything so I do not know how COSMOL treats 2D geometry defined as x,y for one application mode, and as r,z for another

--
Good luck
Ivar


OK, I think this is leading nowhere.
Maybe I will have to think about updating my COMSOL :-)

Meanwhile I created the geometry manually in a new model with the right space dimension.
Took a while but eventually it worked.

Thank you all for your kind help!

Sebastian
[QUOTE] Hi I have just tried to make a 2D model (in v3.5.0.608 =3.5a and v4.1.0.112), save it, and reload it in a new model defined as 2D-axi, I do the same sequence as in your pdf file, except the last step is not there, the geometry is appearing as expected ! could it be a version or a patch missing in your case ? I noticed too, that in 3.5a I could define a 2D geometry and a given application mode, and then add a new application mode to the SAME geometry, but this one defined in 2D-axi. But I havent solved anything so I do not know how COSMOL treats 2D geometry defined as x,y for one application mode, and as r,z for another -- Good luck Ivar [/QUOTE] OK, I think this is leading nowhere. Maybe I will have to think about updating my COMSOL :-) Meanwhile I created the geometry manually in a new model with the right space dimension. Took a while but eventually it worked. Thank you all for your kind help! Sebastian
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 2011年1月16日 GMT-5 06:08
Hi

what is your full version number and have you checked w.r.t. the main comsol site for their patches. I know that going from 3.5 to 3.5a removes the "old"script use, and forces you to matlab only, but there are not that much differences ;) Jumping to v4 is worth it, but it takes some time it's different, but nicer I find

--
Good luck
Ivar
Hi what is your full version number and have you checked w.r.t. the main comsol site for their patches. I know that going from 3.5 to 3.5a removes the "old"script use, and forces you to matlab only, but there are not that much differences ;) Jumping to v4 is worth it, but it takes some time it's different, but nicer I find -- Good luck Ivar
Zhetao Jia
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Posted: 8 years ago 2016年11月15日 GMT-5 00:01
Hi all,

I have solved the problem and just post here in case anyone who meet similar situation in the future.
1. Save the comsol file as .m file
2. Import it into comsol matlab sever
3. Find the line "model.geom('geom1').axisymmetric(false);" and change it to "true"
4. Run the .m file. Open a new Comsol file and connect it to the server. Import.
4. Save the new Comsol file
Hope this helps.

Eric
Hi all, I have solved the problem and just post here in case anyone who meet similar situation in the future. 1. Save the comsol file as .m file 2. Import it into comsol matlab sever 3. Find the line "model.geom('geom1').axisymmetric(false);" and change it to "true" 4. Run the .m file. Open a new Comsol file and connect it to the server. Import. 4. Save the new Comsol file Hope this helps. Eric
Henrik Sönnerlind COMSOL Employee

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Posted: 8 years ago 2016年11月15日 GMT-5 02:16
Hi,

In more recent versions of COMSOL Multiphysics (the original post is about 3.5), there is an even simpler solution:

Start a new 2D axisymmetric model, and then select Geometry->Insert Sequence. You can now just browse to the mph file containing the plane 2D model, and the geometry sequence is imported.

Regards,
Henrik
Hi, In more recent versions of COMSOL Multiphysics (the original post is about 3.5), there is an even simpler solution: Start a new 2D axisymmetric model, and then select Geometry->Insert Sequence. You can now just browse to the mph file containing the plane 2D model, and the geometry sequence is imported. Regards, Henrik

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