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Import STL file?

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Import STL file?

Posted by Luca Paroni at October 03. 2012

hi everybody,

I was wondering: is it possibile to import STL files in salome?

Thanks a lot,

Luca P

 

Re: Import STL file?

Posted by Saint Michael at October 03. 2012

Hi Luca

Yes, Mesh module can import STL meshes.

St.Michael

Re: Import STL file?

Posted by Luca Paroni at October 03. 2012
Thanks Saint Michael,
 
I have another question then. I need to simulate a simple laminar flow in a cylidrical cavity.
I'm a new user of SALOME and I really like it so I want to learn.
We made a PDMS block(silicon) with a channel inside. So today we are going to run the CT scan to get the volume. Do you think is better to take the volume of the channel as STL or his negative (the PDMS block with a cylidrical hole inside)?
 
thanks a lot
 
Luca

Re: Import STL file?

Posted by Saint Michael at October 03. 2012

Unfortunately I am about null in analysis, hope somebody would answer you.

St.Michael

Re: Import STL file?

Posted by Luca Paroni at October 03. 2012

Ah ok. No well the question is do you know if SALOME will consider the STL file as a volume or a surface?

Thanks anyway for your help.

Luca

Re: Import STL file?

Posted by Saint Michael at October 03. 2012

A mesh imported from STL considered to be 2D one within SALOME. If this mesh forms a water-tight domain, 3D mesh can be generated inside it.


St.Michael

Re: Import STL file?

Posted by Luca Paroni at October 03. 2012

Sorry St.Michael,

can you explain in more details what you meant in the two sentences. I think I didn't really understand what you meant. Sorry for that.

 

Luca

Re: Import STL file?

Posted by Saint Michael at October 03. 2012

Well, I speak about abilities of Mesh module. From your question I deduce that you mean something different. Probably, saying "SALOME" you mean "SALOME Meca", but I mean only standard SALOME module one can download from this site, I never dealt  with SALOME Meca. Sorry.

St.Michael

Re: Import STL file?

Posted by Luca Paroni at October 03. 2012

Yes indeed I was considering SALOME Meca. Sorry for the missing information. But so..all that we spoke about I have to consider or in general should be the same? I tried to register of the forum of SALOME-meca but it says sadly:

This forum is not accepting new registrations.

haha. Ok maybe I try to ask here if there are people that use SALOME-meca? do you think is a solution?

 

Luca

Re: Import STL file?

Posted by Andreas Ruopp at January 08. 2014

"A mesh imported from STL considered to be 2D one within SALOME. If this mesh forms a water-tight domain, 3D mesh can be generated inside it."

 

Hello,

 

I have a water-tight domain with stl 2d mesh. How can I generate a 3D mesh?

I tried, but it is also saying "intersecting  triangles". My stl file consists of severel solids.

When I import every solid on its own, it looks perfekt. But I cannot generate 3D mesh, since it is saying, that the model has same edges. Of course, edges from two solids, sharing same edge.

 

Any help is appreciated!

Best,

 

Andy

Re: Import STL file?

Posted by Christophe Bourcier at January 08. 2014

Hi,

To generate a 3D mesh, right click Edit Mesh and add the algorithm NETGEN in the 3D tab.

If there are errors at computation, you can try to:

1. Display the bad mesh elements at the end the compute dialog box, to see where the stl mesh is wrong.

2. Merge the nodes and edges before computing the domain elements.

Christophe

Re: Import STL file?

Posted by Saint Michael at January 08. 2014

Hello Andy

NETGEN can mesh only one domain at once (in case w/o geometry). Hence in your case you can mesh each domain separately and then fuse them into one using "Build compound mesh" command.

St.Michael

Re: Import STL file?

Posted by Andreas Ruopp at January 09. 2014

Hello,

 

many thanks for the fast reply.

Merging nodes I found under:

Modification->Transformation->Merge Nodes

But not Merge Edgs :(

Second question: Is it also possible to remesh a imported stl surface?

Many thanks in advance

Andy

Re: Import STL file?

Posted by Saint Michael at January 09. 2014

Hello Andy

"Build Compound" command has an option to merge nodes and elements. Edges are merged by Modification->Transformation->Merge Elements.

There is no free tool for 2D re-meshing, only commercial plugins ( Mesh->SMESH plugins->ReMesh ...)

St.Michael

Re: Import STL file?

Posted by l-oo-k at January 29. 2014

Hello,

I'm sorry but I am new in Salome :) Could You please help me to create a mesh (hexahedral- would be best) from imported stl 3d model?

I spend some time on that but I can't deal with it :/

Lucas

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Re: Import STL file?

Posted by William Tougeron at January 29. 2014

Hello Lucas,

This works only with Salome 7.3.0 (or later):

    1- Import your STL file into the Geometry module.

    2- Select your imported object in the study tree and go to New Entity > Build > Solid.

    3- In the Mesh module, select your solid in the study tree and go to Mesh > Create Mesh

    4- Set the Algorithm to "Netgen 1D-2D-3D"

    5- Set the Hypothesis (blue little icon on the right) to "NETGEN 3D Parameters" and set the min and max sizes, then click on "OK".

    6- Click on "Apply and Close"

    7- Right-click on your mesh in the study tree ("Mesh_1") and select "Compute".

To edit min and max sizes, look for the Hypothesis called "NETGEN 3D Parameters" (inside Mesh > Hypotheses), right-click on it and select "Edit Hypothesis" then compute again the mesh.

Notice that the edges and nodes already present in your STL file will be also present in your final mesh. But if you reduce your max size, this won't be a problem (cf. enclosed screenshot).

If you don't have Salome 7.3.0 or want to improve the mesh quality, so you can create your solid from scratch in the Geometry module. It is not complicated and necessitate only few hours of learning. It works like any other CAD software.

Hope this helps,

Best regards,

William

Attachments

Re: Import STL file?

Posted by l-oo-k at January 30. 2014

Hello William,

Thank You very much. Your answer is very useful. Unfortunately as You said converting from stl especially from complex shapes has a big disadvantage - "edges and nodes already present in your STL file will be also present in your final mesh".  I'm looking for more useful way to convert shape, for example from blender to solid, that won't affect to mesh as stl does. Creating in geometry module in my opinion is taking much more time, but maybe it's simplest way.

Thank You very much for helping me William :)
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