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Topology issue with projection 2D algorithm

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Topology issue with projection 2D algorithm

Posted by J. Berland at February 08. 2012

Hey,

I have some problems with the projection 2D mesh algorithm. I'm trying to mesh some kind of pipe truncated by a sphere at one of his end. I would like to use quadrangles with prisms on this axis but I have some issues with the projection 2D that says "Unexpected geometry. Topology of source and target faces seems different.". Anybody has an idea on how to deal with this ?

For the mesh I'm using the 3D radial prism algorithm, for the straight face I have quadrangles with a base vertex enforced at one edge. For the curved face I use (I'd like to use) the projection 2D to get the mesh from the straight face.

The pyhthon is attached below.

Thanks,

Attachments

Re: Topology issue with projection 2D algorithm

Posted by Saint Michael at February 09. 2012

Hi,

projection fails as faces are really different, "What Is" says one has 3 edges and the other has 4 edges. An excess edge comes from a degenerated edge at apex of the sphere.

I made 2 changes in your script to make it work:

1) Rotate the sphere to move its apex out of Cut_1.

2) Then the 2D projection passes OK but the mesh is irregular. To fix it I applied SmoothParametricObject() to the mesh on Face_1 before computing 3D mesh.

Enjoy!

St.Michael

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Re: Topology issue with projection 2D algorithm

Posted by J. Berland at February 13. 2012

Really nice ! you're Salome skills are quite impressive !

Thanks a lot for your help,

Julien

Re: Topology issue with projection 2D algorithm

Posted by Bill Wang at March 05. 2017

Dear,

I tried to compute the mesh using the attached python script, but there is always an error like below:

"Invalid input mesh. Incompatible non-structured sub-meshes" for the Prism_3D_4 algorithm.

I am trying to leanr something about the projection algorithm from your case.

I am using Salome 7.8.0

Thank you in advance.

Best Regards,

Bill

Re: Topology issue with projection 2D algorithm

Posted by Saint Michael at March 06. 2017

Here is the script ported to v7.8.0.

St.Michael

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