Personal tools
You are here: Home Forum Use Issue getting 3D Hexa mesh for hollow cone

Issue getting 3D Hexa mesh for hollow cone

Up to Use

Issue getting 3D Hexa mesh for hollow cone

Posted by John Moran IV at June 11. 2019

Hello,

 

I'm trying to mesh hollow cone which will successfully mesh with quads on the outside/inside walls but refuses to go to 3D mesh with Hexahedral (i,j,k). Is this an issue with my choice of 3D meshing? I really want hex elements, gmsh and MG-Hybrid both either force tetra elements or come up with strange patterns that don't reflect the asymmetric nature of the geometry.

 

Any advice or help would be greatly appreciated. Thank you!

 

John

Attachments

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by John Moran IV at Tuesday 21:22

I just realized, I meant to say axisymmetric nature. 

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by Saint Michael at Tuesday 21:25

Hi John

To use Hexahedral (i,j,k) .you need to divide your geometry into blocks. Use Partition operation for that.

St.Michael

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by John Moran IV at Wednesday 20:32

Hi St. Michael,

I used partitions with my cone, something called a butterfly template so that the round tip could actually be done purely with hex elements instead of tetra's. Do you think I can use Hexahedral (i,j,k) with my geometry? I doubt I can divide it into rectangular boxes if that's what it will take to mesh.

John

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by Saint Michael at Thursday 12:48

If well divided, you can use Hexahedral (i,j,k) with your geometry. Topological blocks are enough for that.

St.Michael

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by John Moran IV at Thursday 15:52

Right, but do the topological blocks that I partition need to be square? 

Attachments

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by Saint Michael at Thursday 16:01

Blocks of any shape are suitable.

St.Michael

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by John Moran IV at Thursday 20:28

I've broken up my geometry into blocks using partition (as seen in the attachment from my last post) but when I try to mesh it, I still get an error when attempting the 3D part. The 2D looks really good, I'm not sure if I'm missing something simple or if it's a glitch with Salome.

 

John

 

Attachments

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by Saint Michael at Thursday 20:35

Can you share your data? A saved study would be the best.

St.Michael

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by John Moran IV at Thursday 20:53

The max file size for attachments is 100KB, but my .HDF file is 1.3MB. How can I share the data?

John

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by Saint Michael at Thursday 21:12

Through some cloud.

St.Michael

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by John Moran IV at Thursday 21:24

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by Saint Michael at Thursday 21:40

You did everything right. SALOME behaves bad here. Partition result should be a compound of solids but  for unknown reason SALOME creates one solid. If I use only some of tool faces, it creates the compound of solids as expected. So apply your Partition tools portion by portion to get the compound of solids.

St.Michael

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by John Moran IV at Thursday 22:06

St.Michael

Thanks for the tip, I tried it and it seems to have somewhat worked.

I'm definitely getting closer. I'm having issues meshing the bottom portion due to a 2D wire related problem now. Any ideas? I'm at least getting hex volumes now, though. Attached is the new state.

John

Attachments

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by Saint Michael at Thursday 22:09

Could you share a new geometry?

St.Michael

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by John Moran IV at Thursday 22:11

A new geometry meaning what I just generated from cutting up my cone one tool surface at a time?

John

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by Saint Michael at Thursday 22:12

Yes

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by John Moran IV at Thursday 22:18

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by John Moran IV at Thursday 22:22

I think I may have found the problem, though I'm not sure how to fix it. When I exploded the final partition into solid,s the last two solids on the bottom of the cone are meant to be four solids. This is the region where mesh failure is happening, too.

https://ws.onehub.com/files/gpjdvxdp

Look at how Solid_16 and Solid_17 have a partition line running through them that failed to split them.

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by Saint Michael at Thursday 22:31

I noticed that Partition_3 was not divided by Rotation_4. I managed to get a right result by increasing tolerance (Repair > Limit Tolerance) of Rotation_4 up to 1 before partitioning.

Bye. I go home :)

St.Michael

Re: Issue getting 3D Hexa mesh for hollow cone

Posted by John Moran IV at Thursday 22:33

Thank you so much for your help!

Powered by Ploneboard
Document Actions