# Meshing a flange-like part **URL:** \ **Category:** General Questions\ **Created:** [February 19, 2024, 10:30pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529 "2024-02-19T22:30:26Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![Udzi](https://avatars.discourse-cdn.com/v4/letter/u/779978/32.png) [@Udzi](https://prepomax.discourse.group/u/Udzi)\ **Post date:** [February 19, 2024, 10:30pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/1 "2024-02-19T22:30:26Z")
Hello everyone, I have a couple of questions regarding meshing. What would be the best way of meshing a flange-like part with radial holes, which is technically a piece of the compound part. Do the pieces of the compound part all need to be meshed with the same meshing method? Best case i can see if i could mesh some pieces with the **Extrude** meshing method and the others with the **Transient** meshing method. ![image](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/a/a0cbe25c7fe81e4a3c5ee679d594206957de3754.png) An alternative would be a recommendation how to approach a compound part that can’t be meshed transiently. A smiliar part found online: ![gc-hh-series-coupling-1026659221](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/3/33a57dfe80f5301fa8e6201d477afca4631cb91b.jpeg) ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [February 19, 2024, 10:48pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/2 "2024-02-19T22:48:53Z")
Currently, the rules are that extruded and revolved meshes can’t be used for compound parts so only surface partitions can be used (unless you mesh each part separately and then connect them with tie constraints). On the other hand, transfinite meshes can be applied to compound parts so you can use volume partitions to obtain proper regions (parts) for hex or hex-dominated meshing. Another rule is that each volume (region) used for transfinite meshing must have 5 or 6 faces with 3 or 4 edges each. > [@Summary of Gmsh hex meshing rules](https://prepomax.discourse.group/t/summary-of-gmsh-hex-meshing-rules/1223): > > In this thread, I’d like to collect all the rules that have to be followed to obtain hex meshes with Gmsh in PrePoMax since there are quite a few of them and some may require additional clarification. Please correct me if anything is wrong in my summary. Extruded and revolved meshing can’t be applied to compound parts and thus base face partitions should be used instead of volume partitions. Those base face patches should be selected all at once using e.g. Surface angle selection mode. Ext… ---
**Author:** ![SergioP1975](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/sergiop1975/32/37_2.png) [@SergioP1975](https://prepomax.discourse.group/u/SergioP1975)\ **Post date:** [February 20, 2024, 1:28am UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/3 "2024-02-20T01:28:13Z")
Use second order tets and be happy, refine a little closer to the holes and keep at least three elements in thickness. ---
**Author:** ![arnie](https://avatars.discourse-cdn.com/v4/letter/a/ba9def/32.png) [@arnie](https://prepomax.discourse.group/u/arnie)\ **Post date:** [February 20, 2024, 10:11am UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/4 "2024-02-20T10:11:11Z")
> [@SergioP1975](#): > > Use second order tets and be happy, refine a little closer to the holes and keep at least three elements in thickness. Agreed 🙂 ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [February 20, 2024, 10:58am UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/5 "2024-02-20T10:58:43Z")
another approach, explode the part in CAD to produce shell instead of solid. Mesh that shell with Quasi-structured quad options, then use thickening feature in PrePoMax. Just remember to make sure the thickness in CAD has the same with input value required. ![2024-02-20 17_19_47-GeomApp](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/5/5d75fab4e06836f97dd6a86430d2071b9df05fcf.png) it’s recommended to use hexahedral element whenever possible. PrePoMax have feature for such purpose by methods of extrude/thicken and revolve, transfinite (partitioned). Only use automatic tetrahedral for complex part. Non-conformal or mismatched node mesh between each part can be connected with Tie constraint or Tied contact type. However, it all depending on analysis case. Usually an automatic tetrahedral with quadratic type is sufficient for most case, i.e elastic analysis or nonlinear plastic in small strain conditions. ![2024-02-20 17_25_05-](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/1/1024288bf0f423a77b5d0ecb61268fb6b835017d.png) ![2024-02-20 17_25_35-](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/2/22a81d1778bf9946bbc605d6e2292c8326dfc3b6.png) p.s node numbers and computational resource also. ![2024-02-20 18_36_48-Untitled 1 — LibreOffice Calc](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/1/1cc2374edee9d91b28803d1850a6f0e19948b310.png) ![2024-02-20 18_24_02-](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/6/60658b05a7b2933d8b49178398494c0330d72158.png) ![2024-02-20 18_26_26-](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/e/ea14fe3429987c7046947564b3ba4d2bf214fb64.png) ![2024-02-20 18_27_45-](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/1/1e549e605846aab494a47ccda2ee5b042d57f944.png) ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [February 20, 2024, 11:55am UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/6 "2024-02-20T11:55:19Z")
> [@synt](#): > > p.s node numbers and computational resource also. i added mesh coarsening and refinement at outer (2 layers) and inner (4 layers) radial surface, it generates 30392 nodes. ![2024-02-20 18_48_01-](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/9/9869042789db5765299b492757a30c4af4b6880a.png) ---
**Author:** ![SergioP1975](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/sergiop1975/32/37_2.png) [@SergioP1975](https://prepomax.discourse.group/u/SergioP1975)\ **Post date:** [February 20, 2024, 12:27pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/7 "2024-02-20T12:27:23Z")
If is only a basic static simulation, doesn´t have sense taking so much time doing hexa meshing. ---
**Author:** ![Trevor](https://avatars.discourse-cdn.com/v4/letter/t/258eb7/32.png) [@Trevor](https://prepomax.discourse.group/u/Trevor)\ **Post date:** [February 20, 2024, 1:03pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/8 "2024-02-20T13:03:41Z")
The answer, i guess, comes with experience. The cost of my own time far exceeds the cost of CPU time, ths is the biggest influence on my meshing strategy. For me it results in using hex meshes only where it is obvious to do so, if the geometries are not hex friendly I don’t waste time fighting it. ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [February 20, 2024, 1:09pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/9 "2024-02-20T13:09:51Z")
Some companies require hex meshes in simulations done for them (even when the geometry is complex). But normally yes - it’s often not worth the effort. Of course, it also depends on the mesher’s capabilities. ---
**Author:** ![Trevor](https://avatars.discourse-cdn.com/v4/letter/t/258eb7/32.png) [@Trevor](https://prepomax.discourse.group/u/Trevor)\ **Post date:** [February 20, 2024, 1:56pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/10 "2024-02-20T13:56:58Z")
I love these companies, i get to charge them a premium.😃 ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [February 20, 2024, 2:23pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/11 "2024-02-20T14:23:05Z")
indeed, in the past i have small conversation by email with Klaus of CalculiX also. Internally use hexahedral quadratic (structured) in their professional works. Latest development version of PrePoMax also given possibility for easiness to achieve this, user only needed to do partition which conveniently depend on their CAD software. ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [February 20, 2024, 2:34pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/12 "2024-02-20T14:34:55Z")
alternate method, only by single click as in automatic tetra. It’s a Gmsh hex-dominant methods using R-tree algorithm selection. ![GmshHexDominant](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/c/cf45a23f006701b3ba8fd146bc70d71407717a15.png) ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [February 20, 2024, 2:41pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/13 "2024-02-20T14:41:32Z")
It’s from an older version of Gmsh, right ? Because you’ve mentioned in other threads that this algorithm was removed, then brought back (in 4.12 ?) but doesn’t work so well anymore. ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [February 20, 2024, 2:52pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/14 "2024-02-20T14:52:17Z")
right, older version ones. It’s ran so slow but works and sometimes failed, the newest version seems doing optimization to be faster. Unfortunately, result not good as previously and developer also notified this on progress, prepared or ready in future version (v5.x) ---
**Author:** ![Udzi](https://avatars.discourse-cdn.com/v4/letter/u/779978/32.png) [@Udzi](https://prepomax.discourse.group/u/Udzi)\ **Post date:** [February 20, 2024, 7:47pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/15 "2024-02-20T19:47:33Z")
Thanks for the info everyone. I will see what i can come up with. 🙂 ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [February 20, 2024, 9:49pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/16 "2024-02-20T21:49:17Z")
> [@synt](#): > > developer also notified this on progress, prepared or ready in future version (v5.x) Is there an issue for this in their GitHub repository ? v5.x sounds like a distant future, unfortunately. ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [February 20, 2024, 11:31pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/17 "2024-02-20T23:31:58Z")
i following their [GitLab](https://gitlab.onelab.info/gmsh/gmsh), Twitter, and author papers. Maybe new question can be start by asking result generates compared to previous. i still stick to older version, it a bit laggy (frequently freeze) but working at almost my case. Below simple example of previous test, results shown good agreement with another when maximum stress/strain located at boundary layer. Also, it can be better than structured hexahedra due to inappropriateness of partition. ![test1a](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/7/722fdc0896a7c903f7975a0a18dd299915f61e63.png) ![test1b](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/6/682701752109a254771d4107061d3a6176cab744.png) ![test1c](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/1/1d85c1a0643cf39702ecee6ba78e86525c542b91.png) ps. all element type are linear (C3D8I & C3D4) ---
**Author:** ![Udzi](https://avatars.discourse-cdn.com/v4/letter/u/779978/32.png) [@Udzi](https://prepomax.discourse.group/u/Udzi)\ **Post date:** [February 27, 2024, 5:30pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/18 "2024-02-27T17:30:22Z")
A few days ago i had an awesome idea how this can be done, but in practice it works only partially. I’ve created the flange element and meshed it individually with `Transfinite` meshing algorithm but when i make a compound part it does not work. It somehow sees that there are elements that do not have 5 or 6 faces. Wouldn’t it be logical if all the pieces can be meshed with `Transfinite` algorithm then the whole compound part should be as well? Here’s a way to do it, albeit not sure how good it is. 🙂 ![PrePoMax_2024-02-27_18-29-17](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/5/5bb5d68ea395514bc4f5ce8ce003b3822af4f187.jpeg) ![PrePoMax_2024-02-27_18-29-34](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/e/ee008ff03f93f2b57a657d37b4f33a8c1497f7d7.png) ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [February 27, 2024, 5:52pm UTC](https://prepomax.discourse.group/t/meshing-a-flange-like-part/1529/19 "2024-02-27T17:52:39Z")
> [@Udzi](#): > > It somehow sees that there are elements that do not have 5 or 6 faces. It’s not the only requirement. Each face must have 3 or 4 edges. Sometimes even seam edges (the ones added to cylindrical faces in CAD software) can invalidate this.