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How to use the geometry?

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How to use the geometry?

Posted by 鈴木賢吾 at September 22. 2021

I would like to know something about the geometry feature of salome.

 

Background

I am usually working on CFD calculations.

This time, I used Creo to create the geometry and output it in STL format.

However, the STL became one lump and I could not set the boundary conditions.

So I decided to use salome to divide the shape.

When using salome, I used STEP files because STL has a large number of faces.

 

Procedure

1. Import the STEP file

2.explode to Shell and split Shell to Face

3. Grouped Face by boundary face in Shell

4.export as STL

The result worked.

 

So I have some questions and problems.

 

Problems and questions

Is it possible to edit the tree in the object browser?

 

2. When grouping (shelling) many faces, the shape information hanging in the tree changes and it is difficult to select a new one.

Is there an easy way to do this?

Or is there a way to exclude the grouped parent data from the tree?

 

3.When selecting a small shape, it is difficult to know if it is selected or not.

I turned on Foreground Auto Show in the Preferences.

In this case, the selected shape is easier to see, but I can no longer select Shift in the viewer.

Is there a way to implement this?

 

Re: How to use the geometry?

Posted by Franco Otaola at September 22. 2021

Procedure

1. Import the STEP file => ok

2.explode to Shell and split Shell to Face => you dont need to do this

3. Grouped Face by boundary face in Shell => you dont need to do this
2. you create your groups directly from the step imported. new entry/create group/only surface etc...
3. you should properlly mesh your geoemtry. once you have created your groups go to the mesh section of salome, and mesh each group with netgen 2D (or mefisto) with the same hypothesis for each group this is important to have a watertight mesh (important in cfd)
4. export each group (boundary) as a separate STL in ASCII format. 
5. fuse all the stls files into one, in linux you can use 'cat *.stl >> fusedSTL.stl' (keep in mind that this will fuse all the stls that are in the working folder.)

this workflow should give better results.

2. When grouping (shelling) many faces, the shape information hanging in the tree changes and it is difficult to select a new one.

Is there an easy way to do this?

Or is there a way to exclude the grouped parent data from the tree?

not sure what you mean, you can create a first group, and then in the second you can use the select all faces and then you can right click in the first group created and then deselect this faces in the second group this is the easiest way to greate the groups.

3.When selecting a small shape, it is difficult to know if it is selected or not.

you can use show only selected or hide selected to be sure what you are selecting.

have a look in tobias tutorial part 2 and 3 (https://www.youtube.com/watch?v=CeuFdBqPebc&t=1s) this will help you to better understand how to use salome. enven if you are not going to use the mesh for openfoam it is the same thing.

best regards

 

 

Previously 鈴木賢吾 wrote:

I would like to know something about the geometry feature of salome.

 

Background

I am usually working on CFD calculations.

This time, I used Creo to create the geometry and output it in STL format.

However, the STL became one lump and I could not set the boundary conditions.

So I decided to use salome to divide the shape.

When using salome, I used STEP files because STL has a large number of faces.

 

Procedure

1. Import the STEP file

2.explode to Shell and split Shell to Face

3. Grouped Face by boundary face in Shell

4.export as STL

The result worked.

 

So I have some questions and problems.

 

Problems and questions

Is it possible to edit the tree in the object browser?

 

2. When grouping (shelling) many faces, the shape information hanging in the tree changes and it is difficult to select a new one.

Is there an easy way to do this?

Or is there a way to exclude the grouped parent data from the tree?

 

3.When selecting a small shape, it is difficult to know if it is selected or not.

I turned on Foreground Auto Show in the Preferences.

In this case, the selected shape is easier to see, but I can no longer select Shift in the viewer.

Is there a way to implement this?

 

 

Re: How to use the geometry?

Posted by 鈴木賢吾 at September 27. 2021

Hi,Franco Otaola-san

Thank you for your reply.

There was a national holiday in Japan last week, so my reply was delayed.

Sorry for the delay.

 

Thank you for the clear explanation.

If the number of faces in the STEP or IGES file exceeds 1000, will it be too much work to use the method you gave me or my method?

Or is there an easy way to group the faces if there are many of them?

 

In some of my work, I have STL data that I want to set boundary conditions on, and it is very difficult to do so.

If you have any good advice, please let me know.

 

Regards,

Re: How to use the geometry?

Posted by 鈴木賢吾 at September 27. 2021

Hi,Franco Otaola-san

Thank you for your reply.

There was a national holiday in Japan last week, so my reply was delayed.

Sorry for the delay.

 

Thank you for the clear explanation.

If the number of faces in the STEP or IGES file exceeds 1000, will it be too much work to use the method you gave me or my method?

Or is there an easy way to group the faces if there are many of them?

 

In some of my work, I have STL data that I want to set boundary conditions on, and it is very difficult to do so.

If you have any good advice, please let me know.

 

Regards,

 
 
 

Previously Franco Otaola wrote:

Procedure

1. Import the STEP file => ok

2.explode to Shell and split Shell to Face => you dont need to do this

3. Grouped Face by boundary face in Shell => you dont need to do this
2. you create your groups directly from the step imported. new entry/create group/only surface etc...
3. you should properlly mesh your geoemtry. once you have created your groups go to the mesh section of salome, and mesh each group with netgen 2D (or mefisto) with the same hypothesis for each group this is important to have a watertight mesh (important in cfd)
4. export each group (boundary) as a separate STL in ASCII format. 
5. fuse all the stls files into one, in linux you can use 'cat *.stl >> fusedSTL.stl' (keep in mind that this will fuse all the stls that are in the working folder.)

this workflow should give better results.

2. When grouping (shelling) many faces, the shape information hanging in the tree changes and it is difficult to select a new one.

Is there an easy way to do this?

Or is there a way to exclude the grouped parent data from the tree?

not sure what you mean, you can create a first group, and then in the second you can use the select all faces and then you can right click in the first group created and then deselect this faces in the second group this is the easiest way to greate the groups.

3.When selecting a small shape, it is difficult to know if it is selected or not.

you can use show only selected or hide selected to be sure what you are selecting.

have a look in tobias tutorial part 2 and 3 (https://www.youtube.com/watch?v=CeuFdBqPebc&t=1s) this will help you to better understand how to use salome. enven if you are not going to use the mesh for openfoam it is the same thing.

best regards

 

 

Previously 鈴木賢吾 wrote:

I would like to know something about the geometry feature of salome.

 

Background

I am usually working on CFD calculations.

This time, I used Creo to create the geometry and output it in STL format.

However, the STL became one lump and I could not set the boundary conditions.

So I decided to use salome to divide the shape.

When using salome, I used STEP files because STL has a large number of faces.

 

Procedure

1. Import the STEP file

2.explode to Shell and split Shell to Face

3. Grouped Face by boundary face in Shell

4.export as STL

The result worked.

 

So I have some questions and problems.

 

Problems and questions

Is it possible to edit the tree in the object browser?

 

2. When grouping (shelling) many faces, the shape information hanging in the tree changes and it is difficult to select a new one.

Is there an easy way to do this?

Or is there a way to exclude the grouped parent data from the tree?

 

3.When selecting a small shape, it is difficult to know if it is selected or not.

I turned on Foreground Auto Show in the Preferences.

In this case, the selected shape is easier to see, but I can no longer select Shift in the viewer.

Is there a way to implement this?

 

 

 

Re: How to use the geometry?

Posted by Franco Otaola at September 27. 2021

mmm well, the best approach (I can imagine) you can use is to create a python script and use different functions (filters) of the geometry module to construct your different patches.in case of STLS, it is more complicated (I usually use salome to create my stls, so I do not have a lot of knowledge about these...) but you could approximate your geometry with smooth surfaces but if the stl is really complex in geometry, outside of manual selection, i do not know....

 

good luck with it, and dont hesitate to post if you find a solution, so other people can read about it :) 

 

Previously 鈴木賢吾 wrote:

Hi,Franco Otaola-san

Thank you for your reply.

There was a national holiday in Japan last week, so my reply was delayed.

Sorry for the delay.

 

Thank you for the clear explanation.

If the number of faces in the STEP or IGES file exceeds 1000, will it be too much work to use the method you gave me or my method?

Or is there an easy way to group the faces if there are many of them?

 

In some of my work, I have STL data that I want to set boundary conditions on, and it is very difficult to do so.

If you have any good advice, please let me know.

 

Regards,

 

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