Hello to you all!
I have this shape and I do not know how to obtain a hexahedral mesh. In the second picture I tried to explain what I did so far (imposing element size on edges and partition it with a plane), but I can’t get the mesh I want. Do you have any suggestions?
Thank you
Bonjour ,
Voici une proposition de découpage dans shaper (on peut facilement faire plus jolie) :
Dans Smesh , Créer un maillage avec pour hypothèse générale 3D : Extrusion 3D
Puis, rajouter un sous maillage de la face prédécoupée avec une hypothèse 2D : gmsh2D quasi-structured .
Mohamed
Bonjour et merci pour votre aid!
Je crois que c’est presque bien, mais cet maillage est utile just pour la partie avec des cylindres coupes. Dans la partie sans cylindres ils seront des errors, je m’attend.
Excusez mon français, je l’utilise rarement!
Hello,
as you mention that you dont use french a lot, I allow myself to answer in English (do not hesitate if need it I can answer in french)
you need simply to add extra blocks, that will be extruded on one side and not the other (the blocks for the inside the circles. so something like this:
so you will get all hexahedrons, and you can get a fully hexa mesh without too much hussle.
I did the blocking really fast, so it is quite low quality but so you can understand how to do it.
another approach, (same idea) but higher aspect ratio of the blocks
also (would recommend using quadrangle mapping instead of quasi struc quad it gives more control over the mesh… but it is a personal opinion
Thank you!
From the rendering I think that this type of partition should be done on my initial partition plane and then extrude in both directions? Right?
As for French! I can read it perfectly, but I am a bit rusty in writing it 
you create it in the ‘intersection’ of the two parts, and to one side you extrude everything, to the other ‘everything except what is inside the tubes’
regards.
If you REALLY want to go fancy, here is the best decomposition I came up.
it has higher valence nodes, but a way more ‘homogeneous’ sizes… between edges of the blocks.
regards
Thank you! That’s really complex. I’ll try and see what I get. I am working with python scripts in order to automatize the mesh generation.
the good thing abut the last block decomposition, is that you can scale up to whatever size you prefer by simply copying and moving it around. (in any case all the geometries will give a reasonable good mesh)
hope it helps!
Another question. Suppose that one or two of the cylinders have a bent shape. Then the extrude will not work. Should I use plane partition in this case?
depends if it is a loft over a path, then you can have ‘curved’ blocks. if it is a rotation or something like that (lets say straight horizontal, 90° curved bend, straight vertical), then you will need to divided into (instead of 5 blocks for a o-grid mesh) to 15 (3x5) before the bend begins, and after the bend ends. easy way to be sure, your blocks should have always 6 faces and 12 edges. (it is not mandatory but for simplification and better understanding of the process)
It is over a path. Let’s see what I get and maybe return.
Anyhow thank you all for your help until now!
if it is a path and you have several ‘lines’ (so a path with vertexes in the middle) at each vertex you will need to cut your block, if you simply have a path that does not have ‘middle’ vertex you can get away with the original blocks
