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To concave or not to concave, this is the answer!

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Old   September 22, 2010, 22:55
Default sHM works without snapEdge!
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Ziad Boutanios
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All you have to do is set maxConcave to a really small value. At least it seems to be the answer for getting a snappyHexMesh mesh without jagged/ragged edges on a rectangular geometry, without having to resort to snapeEdge.

Having spent some time looking at jagged/ragged edges I noticed that they boil down to faces with relatively higher concaveness. So armed with this hunch I started lowering the concaveness parameter maxConcave and noticed that the degree of jaggedness/raggedness decreased along with it. The magic number turned out to be 1 degree or maxConcave = 1.

The case is attached with all setup files for those who want to try it. Don't forget to run blockMesh first.

Now this is not guaranteed to work for everything and still needs to be tested for other geometries, such as pyramidal shapes for instance. It also does not mean that there is no such bug in sHM since OF is supposed to allow for concave faces and sHM should just work with them. The fix for this presumed bug could however turn out to be a very low local maxConcave for faces touching the line intersection of two surfaces.
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File Type: jpg straightEdges.jpg (97.9 KB, 89 views)
Attached Files
File Type: gz testBuilding.tar.gz (7.7 KB, 13 views)

Last edited by ziad; September 23, 2010 at 11:29. Reason: added figure
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