Convert space between lines to Solid or surface

Alessandro Hülser

Hello,

I´m new at COMSOL. My first question according to the geometry is the following...

I built a parametriced Body with Lines. Now i want to make the space between the lines to surfaces or make the whole space between the lines to one solid. But with the convert function it doesn´t work. Can anybody help me?

Thankyou!


7 Replies Last Post 2017年9月14日 GMT-0400上午11:04
Jeff Hiller COMSOL Employee
Posted: 1 week ago 2017年9月14日 GMT-0400上午8:32
Updated: 1 week ago 2017年9月14日 GMT-0400上午8:46

Hello Alessandro, I am assuming that you are working in 2D, or in a workplane (if in 3D) - otherwise bounding lines are not enough to uniquely define surfaces. If so, the approach you are describing is correct and illustrated by the attached file. This suggests that you'll want to post you .mph file so other users of the Discussion Forum can see exact how you are going about it (Perhaps there is a gap somewhere, etc, it's hard to tell without the ability to play with your file). Best, Jeff

Hello Alessandro, I am assuming that you are working in 2D, or in a workplane (if in 3D) - otherwise bounding lines are not enough to uniquely define surfaces. If so, the approach you are describing is correct and illustrated by the attached file. This suggests that you'll want to post you .mph file so other users of the Discussion Forum can see exact how you are going about it (Perhaps there is a gap somewhere, etc, it's hard to tell without the ability to play with your file). Best, Jeff


Alessandro Hülser
Posted: 1 week ago 2017年9月14日 GMT-0400上午8:45

Hello Jeff,

here you can see my model. Thanks for your help!

Hello Jeff, here you can see my model. Thanks for your help!


Jeff Hiller COMSOL Employee
Posted: 1 week ago 2017年9月14日 GMT-0400上午9:11
Updated: 1 week ago 2017年9月14日 GMT-0400上午10:07

I'll refer to my earlier post: in 3D, lines do not uniquely define surfaces. If the surfaces you are trying to create are planar (which seems obvious to me but is not obvious to a computer...), you can create them in a 3D geometry by working in workplanes. It's bit tedious because to follow that recommendation you will need to create 6 workplanes, etc. But if indeed the surfaces you want to create are planar, your geometry can be created in a single step using the "Pyramid" tool, and I would recommend you go that route instead of the workplane route. Best, Jeff

I'll refer to my earlier post: in 3D, lines do not uniquely define surfaces. If the surfaces you are trying to create are planar (which seems obvious to me but is not obvious to a computer...), you can create them in a 3D geometry by working in workplanes. It's bit tedious because to follow that recommendation you will need to create 6 workplanes, etc. But if indeed the surfaces you want to create are planar, your geometry can be created in a single step using the "Pyramid" tool, and I would recommend you go that route instead of the workplane route. Best, Jeff

Alessandro Hülser
Posted: 1 week ago 2017年9月14日 GMT-0400上午9:54

Hey Jeff,

i was also thinking of using the pyramid tool. But I want my model to be variable which means, I want to play with the Volume, the height and the angle of my volumebody. Thats why i chose this a little bit strange method with all the lines. So now in my parameters I can change for example the Volume - click draw all - and then my model changes automatically. I´m not sure if that also works with the pyramid tool...??

Alessandro

Hey Jeff, i was also thinking of using the pyramid tool. But I want my model to be variable which means, I want to play with the Volume, the height and the angle of my volumebody. Thats why i chose this a little bit strange method with all the lines. So now in my parameters I can change for example the Volume - click draw all - and then my model changes automatically. I´m not sure if that also works with the pyramid tool...?? Alessandro

Jeff Hiller COMSOL Employee
Posted: 1 week ago 2017年9月14日 GMT-0400上午10:06

Absolutely. See the attached file.

Absolutely. See the attached file.


Alessandro Hülser
Posted: 1 week ago 2017年9月14日 GMT-0400上午10:57
Updated: 1 week ago 2017年9月14日 GMT-0400上午11:03

Looks much easier than my model. But one thing - which is important for me - doesn´t work anymore with your model. When I change for example the Volume V_sp or alpha in my parameter list I get an error and the model doesn´t change. This was possible with my model...You have an idea, how this could work?

edit - now it´s working! Thank you very much for your solution!

Looks much easier than my model. But one thing - which is important for me - doesn´t work anymore with your model. When I change for example the Volume V_sp or alpha in my parameter list I get an error and the model doesn´t change. This was possible with my model...You have an idea, how this could work? edit - now it´s working! Thank you very much for your solution!

Jeff Hiller COMSOL Employee
Posted: 1 week ago 2017年9月14日 GMT-0400上午11:04
Updated: 1 week ago 2017年9月14日 GMT-0400上午11:04

For completeness sake, and to somewhat walk back what I posted earlier, I should say that there is a way to create surfaces that are not planar based on bounding lines. It consists in using the "Cap Faces" capability. Note that Cap Faces is only available if your license includes one of COMSOL's optional CAD import products (i.e. one of the following products: CAD Import Module, Design Module, or one of the LiveLink for CAD packages).

If the bounding lines happen to be planar, Cap Faces will create the planar surface you expect. If they are not, COMSOL picks one of the possible surfaces.

The use of Cap Faces is illustrated in the attached file, where I moved one of the vertices to skew some of the faces.

For more info on Cap Faces, see also https://www.comsol.com/blogs/meshing-cap-off-for-cap-on/ .

For completeness sake, and to somewhat walk back what I posted earlier, I should say that there is a way to create surfaces that are not planar based on bounding lines. It consists in using the "Cap Faces" capability. Note that Cap Faces is only available if your license includes one of COMSOL's optional CAD import products (i.e. one of the following products: CAD Import Module, Design Module, or one of the LiveLink for CAD packages). If the bounding lines happen to be planar, Cap Faces will create the planar surface you expect. If they are not, COMSOL picks one of the possible surfaces. The use of Cap Faces is illustrated in the attached file, where I moved one of the vertices to skew some of the faces. For more info on Cap Faces, see also https://www.comsol.com/blogs/meshing-cap-off-for-cap-on/ .

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