Mesh individual elements one at a time with different triangle edge length

Sasha1296

Hello 

One thing I couldn't find in the manual is how to mesh different objects with different triangle edge lengths? 

What I am trying to do is mesh different objects differently because I have some large cubes that don't need a very fine mesh 

but I also have some cubes that are very small that need a much smaller mesh size

 

What I am trying to do is something like this based on a previous post: 

  

-- for loop that will create many cubes here base on index i

 

  temp_cube = project.Geometry:AddCuboid(cf.Point(x_pos_list, y_pos_list, 0), length_, length_, length_)

  MeshSettings = project.Mesher.Settings
  properties_m = MeshSettings:GetProperties()
  properties_m.MeshSizeOption = cf.Enums.MeshSizeOptionEnum.Custom
  properties_m.TriangleEdgeLength = SOME_STRING_BASED_ON_CUBE_SIZE  -- ex: '0.1' or '0.2', etc 
  MeshSettings:SetProperties(properties_m) 
  project.Mesher:Mesh(temp_cube)

 

-- end of for loop 

 

where the last command  project.Mesher:Mesh(temp_cube) only meshes the temp_cube in question and doesn't mesh any other objects

also I have access to the cube number in this loop in case that is useful

 

 

Mel

Search in the ExampleGuide.pdf for 'local mesh'

Madelé

If you prefer using a for loop like shown above to loop over geometry parts (instead of setting local mesh sizes), you can use MeshSelective:

 project.Mesher:MeshSelective({temp_cube},{})

 

Sasha1296

I tried these variations: 

 

          -- for loop with index i that creates many cubes here 

 

            mesh_length = '0.2'
            mesh_length_ = 0.2
            if (length<0.25)
            then
                mesh_length = '0.01'
                mesh_length_  = 0.01
            end
            cube_count = cube_count + 1  
            temp_cube = project.Geometry:AddCuboid(cf.Point(x_pos_list-length_, y_pos_list, 0), length_, length_, length_)

 

           for key,value in pairs(temp_cube.Faces) do    -- also tried temp_cuge.Edges
              value.LocalMeshSize = mesh_length_
           end

 

            project.Mesher:MeshSelective({temp_cube} ,{})

 

           -- for loop with index i that enes here

 

 

 

 

And a couple variations of the following: 

 

 

 

 

          -- for loop with index i that creates many cubes here 

 

            mesh_length = '0.2'
            mesh_length_ = 0.2
            if (length<0.25)
            then
                mesh_length = '0.01'
                mesh_length_  = 0.01
            end
            cube_count = cube_count + 1  
            temp_cube = project.Geometry:AddCuboid(cf.Point(x_pos_list-length_, y_pos_list, 0), length_, length_, length_)

            

            MeshSettings = project.Mesher.Settings
            properties_m = MeshSettings:GetProperties()
            properties_m.MeshSizeOption = cf.Enums.MeshSizeOptionEnum.Custom
            properties_m.TriangleEdgeLength = mesh_length
            MeshSettings:SetProperties(properties_m) 
            project.Mesher:MeshSelective({temp_cube} ,{})

            -- also tried with the previous project.Mesher:Mesh()

 

           -- for loop with index i that enes here

 

 

 

 

Unfortunatly in all these cases it seems that the smallest cubes don't mesh finely though, the smallest cube in one simulation for example had only 12 triangles dspite it's length being 0.18. My goal is to get it so that each cube will mesh to at least 5 triangles per face 

 

Mel

Please attach an example cfx

Sasha1296

Ok 

The measurement attempt cfx file is mosty a blank file used to generate a lot of other files 

measurmen attempt 1 lua is the corresponding lua script 

the Cad_138_..... stuff.cfx is one of the output example files that gets generated in the results folder

Unable to find an attachment - read this blog

Mel

Here I have set a local mesh size on the faces of the small cuboid of 1/5th of the face length or 0.18/5.

<?xml version="1.0" encoding="UTF-8"?>

 

Sasha1296

Is there a way to do this via lua script? 

I am planning to generate about 1,000 to 10,000  .cfx files in the results folder with random cubes as defined in lua script in the last post 

 

Edit: 

Also just as a thought, could the issue be that I'm not using some variation of the command(I'm not sure how to use it): 

value.LocalMeshSizeEnabled = true in the for loop from the previous post: 

 

           for key,value in pairs(temp_cube.Faces) do    -- also tried temp_cuge.Edges
              value.LocalMeshSize = mesh_length_
           end

Madelé

Yes, the setting can be applied using a Lua script.

 

If you are not familiar with the API, please refer to the Example Guide for the Introduction to Application Automation. You can also use macro recording in CADFEKO to record the scripting equivalent of performing steps in the user interface - look for 'Macro Recording' in the User Guide.

 

For the option shown above, refer to the CADFEKO API documentation. Go to the Face object. It has the properties LocalMeshSize and LocalMeshSizeEnabled.

 

An alternative could be meshing the cubes one-by-one, which is what you initially set out to do. But then you have to change the mesh size for each cube if you want the cubes to have different mesh sizes! Either set local mesh sizes and mesh the whole model once (using Mesh), or mesh the cubes one-by-one (with MeshSelective) using different mesh sizes for each meshing operation.

 

In the script you attached above, you are using a custom mesh size of 0.2 (and in the other comment two values: 0.01 and 0.2). It would be fairly easy to vary the mesh size based on the cube length with something like:

 mesh_size = tostring(Length_list[cube_index]/2)

Note: You did not iterate over the cubes in the attached script, so maybe follow the option of setting a local mesh size for each cube and meshing the model once.

Sasha1296

the for loop creates cubes one at a time I guess that's what I meant,

 

Edit:

I have a for loop: for i = 1, 6 do

and buried inside of it is: temp_cube = project.Geometry:AddCuboid(cf.Point(x_pos_list-length_, y_pos_list, 0), length_, length_, length_)

and after creating each cube I want to mesh it individually 

 

You wrote: 

 

'An alternative could be meshing the cubes one-by-one, which is what you initially set out to do. But then you have to change the mesh size for each cube if you want the cubes to have different mesh sizes! Either set local mesh sizes and mesh the whole model once (using Mesh), or mesh the cubes one-by-one (with MeshSelective) using different mesh sizes for each meshing operation.'

 

That's the issue I've been having, when I run the script in the many configurations I've tried, the script produces cubes but the meshing is not local to the cubes based on size. 

 

I've been trying to either set local mesh sizes and mesh the whole thing at the end, but the smallest cubes still don't have the mesh I wrote into the script (0.01) versus the mesh for the other cubes which is 0.2

 

this is what I tried when I tested: 

 

         for key,value in pairs(temp_cube.Faces) do    -- also tried temp_cuge.Edges
              value.LocalMeshSize = mesh_length_
           end

but it didn't produce cubes with different mesh sizes based on the length of the cubes  when I ran it

Also I tried the other method which is: 

 

            MeshSettings = project.Mesher.Settings
            properties_m = MeshSettings:GetProperties()
            properties_m.MeshSizeOption = cf.Enums.MeshSizeOptionEnum.Custom
            properties_m.TriangleEdgeLength = mesh_length                                               -- Based on cube size 
            MeshSettings:SetProperties(properties_m) 
            project.Mesher:MeshSelective({temp_cube} ,{})

 

But again the cubes don't seem to mesh differently depending on their length

I can't seem to figure out why this is? 

 

 

Edit 2: 

 

perhaps I'm just missing a simple command like: 

project.Geometry.LocalMeshSizeEnabled = true

but I can't figure out if that's the case or how to use this command

Madelé

Maybe the code explains it better.

 

 

It might not do exactly what you want, but it should illustrate the concept.

Unable to find an attachment - read this blog

Sasha1296

Thank you MvdM it workes! 

I ran your script and it worked, the issue with my script looks like was in the line properties_m.TriangleEdgeLength = mesh_length

not in any weird settings that I thought the issue might be in

now  I instead set the triangle edge length to = length_/5 it generates a fine mesh for all of the cubes!