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Domain Creation Problem

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Old   May 27, 2014, 07:47
Cool Domain Creation Problem
Vanessa Herwig
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i have a question regarding the below picture. I wanted to create a unstructured Domain between the two circles of connectors but when i create them with the following command, I get a really weird mesh next to the two connecting cons.

set DomOnSurfaceMode [pw::DomainUnstructured createFromConnectors -reject _TMP(unusedCons) -solid[list $_CN(23) $_CN(25) $_CN(27) $_CN(28)]]
Now I am looking for something similar to the "Project" command that i can ensure that the domain is always on the shape of the circle.

Of course when i am creating a structured mesh there is no problem of the shape. Might it be possible to just 'translate' the structured mesh into a unstructured?

Which way might be the easier way to create the unstructured domain in this special case?

Thanks for your replies.

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Old   June 1, 2014, 18:24
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John Chawner
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Hi Vanessa:

If I understand you correctly, you're saying that the shape of the 180 degree unstructured domain on the top of your "3D disc" has a funny shape. I think I can see that in the picture. That's because the unstructured method needs an underlying geometry (database in our terminology) to ensure that it has the correct shape. The structured domain on the bottom half of your disc has the correct shape due to the nature of how the structured grid methods work.

So I suggest that you create a database surface (surface of revolution) by rotating one of the straight lines that connects the two circles by 180 degrees around whatever the center of your geometry is. Then you can create the unstructured domain using On DB Entities and it will automatically have the correct shape. Or you could simply project what you have onto it.

Again, this is caused by the nature of the Delaunay algorithm that creates the unstructured surface mesh. You will see this for virtually any shape that looks topologically like a cylinder.

Hope this helps.
John Chawner / /
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domain, shape

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