What I just think about:
I just deleted all the lines in my elements-list where area is <=
0.000000001. Doesn't that mean that I have small holes in my surface
mesh now? How is Gmsh able to work with this? I just don't understand
why this makes a difference compared to just check if area is = 0
Steffen
Am 18.03.2014 21:41, schrieb Steffen Becker:
> Hi,
> puh, that's weird:
> First I checked my triangles if their area is > 0 (to get the ones
> which are aligned). This didn't helped as I said in my last mail. Now
> I (just for fun) checked if the area > 0.000000001 and now it works -
> but I don't know why this is such a difference?!
>
> Anyway, thanks for your help!
> Steffen
>
> Am 18.03.2014 10:57, schrieb Zenker, Dr. Matthias:
>>
>> Hi Steffen,
>>
>> there are still ill-defined triangles, e.g. 2319, 2320, 2321. You can
>> find that out by yourself by inspecting your mesh with gmsh in the
>> way I described in my last mail.
>>
>> Remark: checking "surface faces" can help to examine the surface.
>>
>> HTH,
>>
>> Matthias
>>
>> *Von:*Steffen Becker [mailto:steffenbecker87 at yahoo.de]
>> *Gesendet:* Montag, 17. März 2014 22:39
>> *An:* Zenker, Dr. Matthias
>> *Cc:* Roman Fratczak; gmsh at geuz.org
>> *Betreff:* Re: [Gmsh] Error : Self intersecting surface mesh,
>> computing intersections (this could take a while)
>>
>> Hi Matthias,
>>
>> thank you for your help!
>> I think I successfully deleted all the triangles with zero surface.
>> Unfortunately the same error still appears (but at least with much
>> less intersections). You find my new .msh file in the appendix. Do
>> you have more ideas?
>>
>> Regards,
>> Steffen
>>
>> Am 17.03.2014 11:37, schrieb Zenker, Dr. Matthias:
>>
>> Hi Steffen,
>>
>> I think you have ill-defined triangles in your mesh. For example,
>> there is a triangle 15328 which contains the nodes 7358, 7359,
>> and 7360. But these nodes are aligned, so the triangle has zero
>> surface. I would suspect this kind of problem to be the cause for
>> the failure. I discovered that by examining your mesh after
>> merging the intersect.pos, and by displaying node labels and
>> surface labels in gmsh. I saw that this triangle was not visible,
>> just its label, and searched for "15328" in your msh file to see
>> what nodes it contains.
>>
>> You should make sure that this kind of thing cannot happen when
>> you define the surface mesh.
>>
>> HTH,
>>
>> Matthias
>>
>> *Von:*Steffen Becker [mailto:steffenbecker87 at yahoo.de]
>> *Gesendet:* Montag, 17. März 2014 11:20
>> *An:* Zenker, Dr. Matthias
>> *Cc:* Roman Fratczak; gmsh at geuz.org <mailto:gmsh at geuz.org>
>> *Betreff:* Re: [Gmsh] Error : Self intersecting surface mesh,
>> computing intersections (this could take a while)
>>
>> Here it is.
>>
>> Am 17.03.2014 11:14, schrieb Zenker, Dr. Matthias:
>>
>> Hi Steffen,
>>
>> I found out: Outlook is wrong.
>>
>> I just discovered a small info saying that Outlook thinks
>> that my_file.msh is insecure and that it has deleted the
>> attachment (Grrrr). So the fault was on my side, sorry. Could
>> you try to send it again with a changed extension, e.g.
>> rename it to my_file.msh.txt?
>>
>> Matthias
>>
>> *Von:*Steffen Becker [mailto:steffenbecker87 at yahoo.de]
>> *Gesendet:* Montag, 17. März 2014 10:55
>> *An:* Zenker, Dr. Matthias
>> *Cc:* Roman Fratczak; gmsh at geuz.org <mailto:gmsh at geuz.org>
>> *Betreff:* Re: [Gmsh] Error : Self intersecting surface mesh,
>> computing intersections (this could take a while)
>>
>> Hi Matthias,
>>
>> I don't know what's wrong here.
>> When I check my mails, there is a .msh file in the mail from
>> 12.03.2014 18:21 and also one in the mail from 14.03.2014 12:33.
>> Finally, I sent you again a .msh file in this mail. Do you
>> receive it?
>>
>> Steffen
>>
>>
>> Am 17.03.2014 09:52, schrieb Zenker, Dr. Matthias:
>>
>> Hi Steffen,
>>
>> in the mail you mention there is only a geo file...
>>
>> Matthias
>>
>> *Von:*Steffen Becker [mailto:steffenbecker87 at yahoo.de]
>> *Gesendet:* Freitag, 14. März 2014 21:09
>> *An:* Zenker, Dr. Matthias
>> *Cc:* Roman Fratczak; gmsh at geuz.org <mailto:gmsh at geuz.org>
>> *Betreff:* Re: [Gmsh] Error : Self intersecting surface
>> mesh, computing intersections (this could take a while)
>>
>> Hi Matthias,
>>
>> hm, I sent it on 12.03.2014 18:21, don't know what went
>> wrong.
>> As you see, I created a ASCII .msh file as explained in
>> the documentation, so I hope it's correct.
>> What can I do now?
>>
>> Steffen
>>
>> Am 14.03.2014 13:05, schrieb Zenker, Dr. Matthias:
>>
>> Hi Steffen,
>>
>> there was no msh file in any of your mails.
>>
>> Depending on what is in the msh file, your steps seem
>> correct to me.
>>
>> Matthias
>>
>> *Von:*Steffen Becker [mailto:steffenbecker87 at yahoo.de]
>> *Gesendet:* Freitag, 14. März 2014 12:33
>> *An:* Zenker, Dr. Matthias
>> *Cc:* Roman Fratczak; gmsh at geuz.org
>> <mailto:gmsh at geuz.org>
>> *Betreff:* Re: [Gmsh] Error : Self intersecting
>> surface mesh, computing intersections (this could
>> take a while)
>>
>> Hi Matthias,
>>
>> I think you are talking about your mail from
>> 12.03.2014 09:59 ?
>> In one of my last mails I already sent you a
>> selfcreated .msh file - but the 3D mesh still failes.
>> The intersect.pos shows me some
>>
>> intersections, but when I check my nodes for
>> duplicates I can't find any.
>> Hope my steps are correct:
>> - create "my_file.msh" with my python script and
>> check it for nodes duplications -> none found
>> - open "my_file.geo" in Gmsh
>> - do "Modules" -> "Mesh" -> "3D"
>> - receive error message
>> - merge "intersect.pos" and see some intersections
>> but I don't know why because the are no duplicated nodes
>>
>> Steffen
>>
>>
>> Am 14.03.2014 09:50, schrieb Zenker, Dr. Matthias:
>>
>> Hi Steffen,
>>
>> you should be able to generate a filled volume
>> mesh if you follow my suggestion from the other mail:
>>
>> Write the 2D mesh in gmsh format (e.g. as
>> outerface.msh, gmsh documentation for more info
>> on the msh format) and merge that one instead of
>> the myfile.ply2 file, leaving the other command
>> lines in your .geo file as they are. If you then
>> do a 3D mesh, gmsh will take the 2D mesh as
>> defined in your file. You can then refine the
>> mesh if you wish.
>>
>> HTH,
>>
>> Matthias
>>
>> *Von:*Steffen Becker
>> [mailto:steffenbecker87 at yahoo.de]
>> *Gesendet:* Mittwoch, 12. März 2014 20:00
>> *An:* Roman Fratczak
>> *Cc:* Zenker, Dr. Matthias; gmsh at geuz.org
>> <mailto:gmsh at geuz.org>
>> *Betreff:* Re: [Gmsh] Error : Self intersecting
>> surface mesh, computing intersections (this could
>> take a while)
>>
>> Hi,
>>
>> I'm so sorry for all time you spent with my
>> problem, but now I see: We talk at cross. It's my
>> fault, I didn't explained correctly what I need.
>> I want to receive a *filled* volume mesh.
>> I created 2 files (steffen.stl and steffen2.stl)
>> with my python script.
>> With steffen.stl I successfully could create such
>> a filled volume mesh as seen in steffen.msh.
>> When I try exactly the same with steffen2.stl
>> then I get the error message in the subject (and
>> the surface mesh doesn't get filled).
>> So that's why the .iges file you sent me isn't
>> what I need.
>>
>> Sorry for all this confusion,
>> Steffen
>>
>>
>> Am 12.03.2014 18:53, schrieb Roman Fratczak:
>>
>> Steffen,
>>
>> I did a volume based on your surface mesh -
>> see attached IGES (compressed with 7-zip).
>> After reading it into GMSH, you can create
>> the 1D, then 2D and finally 3D mesh with no
>> errors.
>>
>> You can do the same using GMSH volume
>> definition (as already wrote)-> it will work,
>> as the fundamental faces are plane triangles.
>>
>> Regards
>> Roman
>>
>>
>> W dniu 12.03.2014 18:27, Steffen Becker pisze:
>>
>> Wrong .geo file, sorry!
>>
>> Am 12.03.2014 18:21, schrieb Steffen Becker:
>>
>> Thank you so far,
>>
>> I create both files: .msh and .geo,
>> but I still get the same error.
>> What's my mistake?
>>
>> Steffen
>>
>> Am 12.03.2014 11:48, schrieb Roman
>> Fratczak:
>>
>> Hi,
>>
>> FYI - you can remove double
>> vertices/edges (or repair) in
>> mesh in FreeCad (for exampe).
>>
>> regards
>> Roman
>>
>>
>>
>> W dniu 12.03.2014 10:17, Steffen
>> Becker pisze:
>>
>> Hi Matthias & Roman,
>>
>> I create a nodes- and
>> elements-list like this:
>> # nodes:
>> N1 0,0,0
>> N2 0,1,0
>> N3 1,0,0
>> N4 0,0,1
>> # elements, which describe
>> triangles:
>> E1 1,2,3
>> E2 2,3,4
>>
>> So I do have double edges
>> (here: between node 2+3).
>> Didn't now that this is a
>> problem for gmsh, sorry.
>>
>> I will try Romans solution
>> asap and give you a feedback.
>> Thank you both!
>>
>> Steffen
>>
>>
>> Am 12.03.2014 09:59, schrieb
>> Zenker, Dr. Matthias:
>>
>> Hi Steffen,
>>
>> I am not totally sure
>> from what you wrote that
>> there are really no
>> duplicated nodes. In
>> gmsh, you need to define
>> the surfaces in a way
>> that neighbouring
>> surfaces/facets with a
>> common border use the
>> _/same/_ nodes to define
>> the border. I could not
>> see from your file if
>> there are duplicated
>> nodes, and would propose
>> that you make sure that
>> there are really no such
>> duplications.
>>
>> If the meshing still
>> fails, then this is a
>> question for the real
>> gurus (Christophe?).
>>
>> HTH,
>>
>> Matthias
>>
>> *Von:*Roman Fratczak
>> [mailto:fratczakroman at o2.pl]
>> *Gesendet:*Mittwoch, 12.
>> März 2014 09:51
>> *An:* Steffen Becker
>> *Cc:* gmsh at geuz.org
>> <mailto:gmsh at geuz.org>
>> *Betreff:* Re: [Gmsh]
>> Error : Self intersecting
>> surface mesh, computing
>> intersections (this could
>> take a while)
>>
>> 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:steffenbecker87 at yahoo.de]
>>
>> Gesendet: Dienstag, 11. März 2014 14:42
>>
>> An: Zenker, Dr. Matthias
>>
>> Cc:gmsh at geuz.org <mailto:gmsh at geuz.org>
>>
>> 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
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>>
>> gmsh mailing list
>>
>> gmsh at geuz.org <mailto:gmsh at geuz.org>
>>
>> http://www.geuz.org/mailman/listinfo/gmsh
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>>
>> gmsh mailing list
>>
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>>
>> http://www.geuz.org/mailman/listinfo/gmsh
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
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>>
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>>
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>>
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>>
>>
>> _____________________________________________________________________
>> ERBE Elektromedizin GmbH
>> Firmensitz: 72072 Tuebingen
>> Geschaeftsfuehrer:
>> Christian O. Erbe, Reiner
>> Thede
>> Registergericht:
>> Stuttgart HRB 380137
>>
>>
>>
>> _____________________________________________________________________
>> ERBE Elektromedizin GmbH
>> Firmensitz: 72072 Tuebingen
>> Geschaeftsfuehrer: Christian O. Erbe, Reiner Thede
>> Registergericht: Stuttgart HRB 380137
>>
>>
>>
>> _____________________________________________________________________
>> ERBE Elektromedizin GmbH
>> Firmensitz: 72072 Tuebingen
>> Geschaeftsfuehrer: Christian O. Erbe, Reiner Thede
>> Registergericht: Stuttgart HRB 380137
>>
>>
>>
>> _____________________________________________________________________
>> ERBE Elektromedizin GmbH
>> Firmensitz: 72072 Tuebingen
>> Geschaeftsfuehrer: Christian O. Erbe, Reiner Thede
>> Registergericht: Stuttgart HRB 380137
>>
>>
>>
>> _____________________________________________________________________
>> ERBE Elektromedizin GmbH
>> Firmensitz: 72072 Tuebingen
>> Geschaeftsfuehrer: Christian O. Erbe, Reiner Thede
>> Registergericht: Stuttgart HRB 380137
>>
>>
>>
>> _____________________________________________________________________
>> ERBE Elektromedizin GmbH
>> Firmensitz: 72072 Tuebingen
>> Geschaeftsfuehrer: Christian O. Erbe, Reiner Thede
>> Registergericht: Stuttgart HRB 380137
>>
>>
>>
>> _____________________________________________________________________
>> ERBE Elektromedizin GmbH
>> Firmensitz: 72072 Tuebingen
>> Geschaeftsfuehrer: Christian O. Erbe, Reiner Thede
>> Registergericht: Stuttgart HRB 380137
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