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-   -   Hexpress: failed feature line recognition (http://www.cfd-online.com/Forums/numeca/128240-hexpress-failed-feature-line-recognition.html)

timfranke January 7, 2014 08:37

Hexpress: failed feature line recognition
 
Hello,

I came across a phenomena and I wonder if someone could tell a work around.
Given a cube where one edge is not completely sharp since after
half of the edge length the sharp edge runs over into a radius
that increases from R=0 to R=max at the corner point.
After importing as stl eleven edges a shown a feature lines but the
single edge decribed above is absent, although I would expect
to see a feature edge that covers half of the cube edge.
From a feature angle point of view the featre edge should be there.

Regards,
Tim

Kaskade January 7, 2014 10:28

A picture would help understand the problem.

But I don't know if a feature edge can just stop, without connecting to other edges.

Do you have to use STLs?

timfranke January 7, 2014 11:52

Just imagine a cube where one edge radius develops from being 0 (sharp)
to a finite value (round). In Hexpress the whole edge is not marked as
a feature line although the first part is perfectly sharp.
If I read in stl the only way to detect feature lines is to evaluate the angle
of surface normals between neigbouring cells. If that angle exceeds a
given threshold then the common edge is a feature line.

Obviously this is treated differently in Hexpress leading to the described deficit.

Importing the geometry as Parasolid leads to the same failure.

Regards,
Tim

Kaskade January 7, 2014 13:44

How about splitting the cube at the point where the edge starts getting rounded?


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