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Conversion of parametric surface to solid

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Hi!

I built a parametric surface in Comsol 4.2 and am now trying to convert it to a solid. If I use the "Convert to Solid"-function the whole object vanishes without an error message. Do I somehow have to close the open boundary of the surface, or am I doing something else wrong?

The model file is attached.

Best regards,
Christian


6 Replies Last Post 21 déc. 2016, 08:00 UTC−5

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Posted: 1 decade ago 14 juil. 2011, 09:50 UTC−4
Your file has the microfluidics module present. A lot of people may not have this module and will get a license error trying to openg it (I did). If you can, just post the file geometry w/o any phsyics.
Your file has the microfluidics module present. A lot of people may not have this module and will get a license error trying to openg it (I did). If you can, just post the file geometry w/o any phsyics.

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Posted: 1 decade ago 15 nov. 2011, 16:57 UTC−5
I have the same problem. Did anyone manage to fix this? Have 4 lines (1 parametric curve & 3 straight lines) which I've connected using a Union. However, I can't convert this figure into a solid. Right now it's just an outline. Here's a copy of my file. I don't have a microfluids module so it shouldn't have the license error issue that the other file had.
I have the same problem. Did anyone manage to fix this? Have 4 lines (1 parametric curve & 3 straight lines) which I've connected using a Union. However, I can't convert this figure into a solid. Right now it's just an outline. Here's a copy of my file. I don't have a microfluids module so it shouldn't have the license error issue that the other file had.


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

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Posted: 1 decade ago 16 nov. 2011, 02:39 UTC−5
Hi

Try the "Geometry - right click - Conversions - Convert to Solid".

By the way you do not need the union in this case, so long the loop is closed its OK

--
Good luck
Ivar
Hi Try the "Geometry - right click - Conversions - Convert to Solid". By the way you do not need the union in this case, so long the loop is closed its OK -- Good luck Ivar

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Posted: 1 decade ago 12 avr. 2012, 19:46 UTC−4
I've been trying to do this too with lines and curves, and the convert to solid doesn't seem to do much. I was able to get a solid using parametric curves and open polygons (instead of lines). That may help.
I've been trying to do this too with lines and curves, and the convert to solid doesn't seem to do much. I was able to get a solid using parametric curves and open polygons (instead of lines). That may help.

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Posted: 8 years ago 16 déc. 2016, 12:41 UTC−5
Hi !
i'm trying to convert a surface geometry to a solid (Geometry - right click - Conversions - Convert to Solid) and every time the following message appear :

"The operation resulted in an empty geometry."

i want to understand why this message appear; please help me to find a solution to this problem.

Best regards
Hi ! i'm trying to convert a surface geometry to a solid (Geometry - right click - Conversions - Convert to Solid) and every time the following message appear : "The operation resulted in an empty geometry." i want to understand why this message appear; please help me to find a solution to this problem. Best regards

Magnus Ringh COMSOL Employee

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Posted: 8 years ago 21 déc. 2016, 08:00 UTC−5
Hi all,

Here is some information and tips for converting nonsolid geometries to solids.

Firstly, a surface cannot be converted to a solid unless it is a closed solid; otherwise, that operation results in an empty geometry.

Also, you cannot convert curves or lines in 3D into a solid directly, but if the curves or lines form a closed curve and that curve lie in a plane, then you can form a surface that you can extrude into a 3D solid. To do so, add a work plane in the same plane as the closed curve, and then, under the Plane Geometry node, add a Cross Section node to make the closed curve appear as a closed curve in the 2D Plane Geometry, where you can then use a Convert to Solid node to convert it into a 2D solid (that is, a 3D surface).

A nonclosed 2D surface can be converted to a solid using extrusion so that it gets a nonzero thickness. With the Design Module, there is also a Thicken feature that can thicken a surface into a (thin) solid.

The problem in the parametric_surface geometry is that the topology is invalid (due to self-intersecting curves). If you use two Parametric Surface nodes instead, with the same settings except that in the first one, the s1 parameter runs from 0 to pi, and in the other, it runs from pi to 2*pi (instead of one parametric surface where s1 runs the full circle from 0 to 2*pi). With that modification, and an active work plane with the bottom surface, you can form a 3D solid using a Convert to Solid node with all three surfaces as the input. With the CAD Import Module, you can use a Cap Faces feature to create a closed surface instead of creating a closing bottom surface in a work plane.

For the TopoBoundary model, the closed 2D curve can be directly converted to a 2D solid using a Convert to Solid node in the latest version of COMSOL Multiphysics, version 5.2a, as well as in version 5.2.

Best regards,
Magnus Ringh, COMSOL
Hi all, Here is some information and tips for converting nonsolid geometries to solids. Firstly, a surface cannot be converted to a solid unless it is a closed solid; otherwise, that operation results in an empty geometry. Also, you cannot convert curves or lines in 3D into a solid directly, but if the curves or lines form a closed curve and that curve lie in a plane, then you can form a surface that you can extrude into a 3D solid. To do so, add a work plane in the same plane as the closed curve, and then, under the Plane Geometry node, add a Cross Section node to make the closed curve appear as a closed curve in the 2D Plane Geometry, where you can then use a Convert to Solid node to convert it into a 2D solid (that is, a 3D surface). A nonclosed 2D surface can be converted to a solid using extrusion so that it gets a nonzero thickness. With the Design Module, there is also a Thicken feature that can thicken a surface into a (thin) solid. The problem in the parametric_surface geometry is that the topology is invalid (due to self-intersecting curves). If you use two Parametric Surface nodes instead, with the same settings except that in the first one, the s1 parameter runs from 0 to pi, and in the other, it runs from pi to 2*pi (instead of one parametric surface where s1 runs the full circle from 0 to 2*pi). With that modification, and an active work plane with the bottom surface, you can form a 3D solid using a Convert to Solid node with all three surfaces as the input. With the CAD Import Module, you can use a Cap Faces feature to create a closed surface instead of creating a closing bottom surface in a work plane. For the TopoBoundary model, the closed 2D curve can be directly converted to a 2D solid using a Convert to Solid node in the latest version of COMSOL Multiphysics, version 5.2a, as well as in version 5.2. Best regards, Magnus Ringh, COMSOL

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