Hi Steffen,
No it is more clear. If you are working with cloud of point, then you
may use Meshlab for surface regeneration. There are many software that
are able to handle in a resonable way the cloud of points (like rhino3D
+ resurf, other). But these are rather commercial.
From the other side - try to do the simplest thing:
Adjust your python script for surface creation in order to save not as
PLY but as GMSH "geo" file using points and lines
Point(1)={0,0,0} ;
Point(2)={0,1,0} ;
...
Line(1) = {1,2};
..
and.. Line Loop & Surface -> Volume ..
Then you will get a volume defined by geometric entities. In this case
is shoul be easier to create a better mesh on surface and then on whole
volume.
Regards
Roman
W dniu 11.03.2014 17:59, Steffen Becker pisze:
Hi,
@ Roman:
some more details:
I have a point cloud given and generate the surface mesh by myself
(with python). I don't know a good algorithm to create a volume mesh
out of this surface mesh - that's why I use gmsh for this task.
I also checked my surface mesh for double vertexes but I didn't find
any. What do you mean with "double egdes"? Isn't there always a
"double edge", because two neighbour facets always have one same edge?!
I will send you a .step or .iges file as soon as I figured out how to
handle the "No OpenCASCADE model found" error.
I'm appending the other mailing history (with Matthias) to this mail -
sorry for that "double mailing", I just forgot one time to "reply to
all" -.-
Anyone else has an idea why the meshing fails?
Regards and thank you a lot,
Steffen
Hi Steffen,
I don't see either why the meshing fails, sorry.
Matthias
-----Ursprüngliche Nachricht-----
Von: Steffen Becker [mailto:[email protected]]
Gesendet: Dienstag, 11. März 2014 14:42
An: Zenker, Dr. Matthias
Cc:[email protected]
Betreff: Re: [Gmsh] Error : Self intersecting surface mesh, computing
intersections (this could take a while)
Oh I'm really sorry, here is the file.
In addition I sent you also the intersect.pos. I don't understand why exactly
these surfaces are problematic and the "neighbour surfaces"
aren't - although they have the same geometry =/
Am 11.03.2014 12:07, schrieb Zenker, Dr. Matthias:
Hi Steffen,
if you don't provide the myfile.ply2, we cannot see your geometry...
You can visualize intersect.pos by merging it to your geometry.
HTH,
Matthias
Am 11.03.2014 14:33, schrieb Roman Fratczak:
Hello,
It is possible, that you will get your geometry in other format?
In your "ply" there is already a surface mesh given. Try maybe use
STEP, IGES,... as input- then it is easer to recalculate the surface
mesh.
In case of need of usage of "a dead mesh" - maybe try first to remesh
it (i.e. in blender with modification Remesh) and/or clean it
(removing double vertexes and edges).
regards
Roman
W dniu 11.03.2014 12:13, Steffen Becker pisze:
Hi,
in the appendix you find my model.
Thanks for help!!
Regards,
Steffen
Am 11.03.2014 11:47, schrieb Roman Fratczak:
Hello Steffen,
Yes. You can try to the first Optimize quality of tetra, or all of
them (just try).
I don't know how your model looks like. If the elements on the
surface are too big, then the solid elements (probably tetragonal)
may be with intersecting edges or faces. Therefore the reducing
size of element may help (especially on the surfaces).
Or- just share your model (ply) -in order to be more precise.
regards
Roman
W dniu 10.03.2014 18:06, Steffen Becker pisze:
Hi Roman,
when you say "enable option: optimize", you mean" Tools -> Options
-> Mesh -> Advanced -> Optimize quality of tetrahedra, Optimize
quality of tetrahedra with Netgen, Optimize high order meshes
(experimental)" ?
And why is reducing element size important? In my case it is
important that the object has such "90 degree corners".
Regards,
Steffen
Am 10.03.2014 16:55, schrieb Roman Fratczak:
Hi Steffen,
If your volume is OK (is really a closed one) - try to:
1. Reduce element size (especially in a curved shapes)
2. Enable option "Optimize" - in mesh options
Regards
Roman
W dniu 10.03.2014 16:41, Steffen Becker pisze:
Hello everyone,
I'm a gmsh beginner and I want to create a 3D volume mesh out of
a given surface-mesh but I got the error message as seen in the
subject. You find my .geo file in the appendix.
Can anyone tell me what I have to do to create a 3D mesh? I even
can't figure out where the intersection are located (don't know
how to read the intersect.pos).
Sorry for my poor english.
Regards,
Steffen
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