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Importing 3D geometric points (In MS Excel) and converting into a surface for extrusion (Solid)

Posted 3 mar 2017, 14:09 GMT-5 Geometry Version 5.2a 14 Replies

Daniel Ocansey
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Hello all,
I want to import geometric points from an MS excel sheet to form a surface. I was able to use the "Interpolation Curve" to import the points but am not able to convert it into a geometric surface. This surface will then be "extrude" to form a solid. Can someone help me get it right? Attached is a simple example. Thank you.

14 Replies Last Post 9 mar 2017, 16:34 GMT-5
Jeff Hiller COMSOL Employee

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Posted: 7 years ago 3 mar 2017, 15:41 GMT-5
Hello Daniel,
For you to be able to extrude an object, you need to draw your surface in a workplane (which also implies that it needs to be planar). The curve you provided as n example is self intersecting, which may cause problems, but from the wording of your post it sounds like that's not the actual curve.

You can sweep a non-planar surface, but you cannot uniquely define a non-planar surface with a curve.
Best,
Jeff
Hello Daniel, For you to be able to extrude an object, you need to draw your surface in a workplane (which also implies that it needs to be planar). The curve you provided as n example is self intersecting, which may cause problems, but from the wording of your post it sounds like that's not the actual curve. You can sweep a non-planar surface, but you cannot uniquely define a non-planar surface with a curve. Best, Jeff
Daniel Ocansey
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Posted: 7 years ago 8 mar 2017, 13:14 GMT-5
I have a unique 3D random (random points) surface generated. Am trying to import this data points into Comsol. This convert the points into a surface and then into a solid by extruding the surface. Thank you.

Example
X Y Z
. . .
. . .
. . .
I have a unique 3D random (random points) surface generated. Am trying to import this data points into Comsol. This convert the points into a surface and then into a solid by extruding the surface. Thank you. Example X Y Z . . . . . . . . .
Jeff Hiller COMSOL Employee

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Posted: 7 years ago 8 mar 2017, 14:02 GMT-5
If I understand what you want to do correctly, you could use an Interpolation function and a Parametric Surface based on that function. What I have in mind is similar to www.comsol.com/support/knowledgebase/838/
but you'd be using an Interpolation function where the example above uses an Elevation (DEM) function.

Jeff
If I understand what you want to do correctly, you could use an Interpolation function and a Parametric Surface based on that function. What I have in mind is similar to https://www.comsol.com/support/knowledgebase/838/ but you'd be using an Interpolation function where the example above uses an Elevation (DEM) function. Jeff
Daniel Ocansey
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Posted: 7 years ago 8 mar 2017, 14:49 GMT-5
Thank you. Currently I have CSV FILE. Do I have to convert it into DEM FILE. If possible how can I convert the file.
Thank you. Currently I have CSV FILE. Do I have to convert it into DEM FILE. If possible how can I convert the file.
Jeff Hiller COMSOL Employee

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Posted: 7 years ago 8 mar 2017, 15:24 GMT-5
Daniel,
Please review my suggestion above: I was saying you'd use an Interpolation function instead of a Elevation (DEM) function. If you have not worked with Interpolation functions before, you'll want to read the section about them in the COMSOL Multiphysics User Guide, version 5.2a. It should give you a good idea of how to proceed.
All manuals are access through File > Help >Documentation.
Best regards,
Jeff
Daniel, Please review my suggestion above: I was saying you'd use an Interpolation function instead of a Elevation (DEM) function. If you have not worked with Interpolation functions before, you'll want to read the section about them in the COMSOL Multiphysics User Guide, version 5.2a. It should give you a good idea of how to proceed. All manuals are access through File > Help >Documentation. Best regards, Jeff
Daniel Ocansey
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Posted: 7 years ago 8 mar 2017, 17:06 GMT-5
Hello Jeff,
Thank you. It did work but the shape of the surface is not exact.


Daniel Ocansey
Hello Jeff, Thank you. It did work but the shape of the surface is not exact. Daniel Ocansey
Nicholas Goldring Certified Consultant
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Posted: 7 years ago 8 mar 2017, 17:20 GMT-5
Out of curiosity, how did you figure out that the shape of your surface was not exactly what it should be and by how much do you think it's off? Did you measure the distance between specific points or boundaries within Comsol? One way that was helpful for me to confirm that geometries are what they should be within Comsol was to run a study using that geometry with a solid mechanics interface but apply no loads. In other words, you'll get a set of variables from the solution that will allow you to plot, interpolate, average etc. to figure out the precise parameters of your geometry without actually deforming it. There is probably an easier way around this an I would imagine that in most scenarios just using the "measure" tool is enough.

Best of luck.
Out of curiosity, how did you figure out that the shape of your surface was not exactly what it should be and by how much do you think it's off? Did you measure the distance between specific points or boundaries within Comsol? One way that was helpful for me to confirm that geometries are what they should be within Comsol was to run a study using that geometry with a solid mechanics interface but apply no loads. In other words, you'll get a set of variables from the solution that will allow you to plot, interpolate, average etc. to figure out the precise parameters of your geometry without actually deforming it. There is probably an easier way around this an I would imagine that in most scenarios just using the "measure" tool is enough. Best of luck.
Daniel Ocansey
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Posted: 7 years ago 8 mar 2017, 17:48 GMT-5
Hello Jeff,
Okay. I will do that. Find attached what Am talking about..

Actual Surface: is the actual figure
Surface after using the Parametric Surface: This is what I see after using the Parametric Surface.

Hello Jeff, Okay. I will do that. Find attached what Am talking about.. Actual Surface: is the actual figure Surface after using the Parametric Surface: This is what I see after using the Parametric Surface.
Jeff Hiller COMSOL Employee

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Posted: 7 years ago 9 mar 2017, 08:09 GMT-5
Hi Nicholas,
As you suspected, you can achieve the same without adding any physics interface, structural mechanics or otherwise. The "trick" is to select "Get Initial Values" in the Study branch. That's enough to let you do all kinds of post-processing on the geometry.
Best,
Jeff
Hi Nicholas, As you suspected, you can achieve the same without adding any physics interface, structural mechanics or otherwise. The "trick" is to select "Get Initial Values" in the Study branch. That's enough to let you do all kinds of post-processing on the geometry. Best, Jeff
Jeff Hiller COMSOL Employee

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Posted: 7 years ago 9 mar 2017, 08:12 GMT-5
Hi Daniel,
Have you tried increasing the number of knots that are used to make the parametric surface?
Jeff
Hi Daniel, Have you tried increasing the number of knots that are used to make the parametric surface? Jeff
Nicholas Goldring Certified Consultant
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Posted: 7 years ago 9 mar 2017, 09:53 GMT-5

Hi Nicholas,
As you suspected, you can achieve the same without adding any physics interface, structural mechanics or otherwise. The "trick" is to select "Get Initial Values" in the Study branch. That's enough to let you do all kinds of post-processing on the geometry.
Best,
Jeff


Ahh okay, thanks Jeff.
[QUOTE] Hi Nicholas, As you suspected, you can achieve the same without adding any physics interface, structural mechanics or otherwise. The "trick" is to select "Get Initial Values" in the Study branch. That's enough to let you do all kinds of post-processing on the geometry. Best, Jeff [/QUOTE] Ahh okay, thanks Jeff.
Daniel Ocansey
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Posted: 7 years ago 9 mar 2017, 14:20 GMT-5
I did try to increase the number of knots. However, It's still the same.
I did try to increase the number of knots. However, It's still the same.
Jeff Hiller COMSOL Employee

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Posted: 7 years ago 9 mar 2017, 15:09 GMT-5
I am afraid I have run out of useful things I can say without interacting directly with your file. I'll invite you to contact our support team support@comsol.com if you need further assistance. Please be sure to provide the mph file involved as well as the underlying data files.
Best,
Jeff
I am afraid I have run out of useful things I can say without interacting directly with your file. I'll invite you to contact our support team support@comsol.com if you need further assistance. Please be sure to provide the mph file involved as well as the underlying data files. Best, Jeff
Daniel Ocansey
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Posted: 7 years ago 9 mar 2017, 16:34 GMT-5
Hello Jeff,
Thank you. I will be forwarding the file to the support unit for assistance.
Hello Jeff, Thank you. I will be forwarding the file to the support unit for assistance.

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