simple 3D example
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simple 3D example  


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06/09/2019 2:58 pm  

I was reading another mesher manual to see how they handle the process of making meshes. In this case, that manual show one of the typical examples, the “bath tub”. The next figure shows the shape of the 3D volume representing this example

In my opinion the way they handle the meshing process involves too many steps. The following is a summary of what is described in that manual:

1.- One needs a full 3D wireframe volume. The example start by opening a DXF file. The model in this file is similar to the previous image. This file by itself involves a significant amount of work, previous to the meshing process!!!

2- One needs to divide the entire domain in smaller volumes. So simple 3D volumes can be meshed. Experience is needed for knowing how to divide the domain in simple volumes.

3.- One needs to create 3D faces surrounding the smaller volumes.

4.- Ones needs to creates a series of smaller 3D volumes.

5.- Finally, one needs to mesh each volume, and the collection of them define the model domain. SO MANY STEPS!!!


In contrast, I´m going to show you how to do this example from scratch with Geo Meshing. WITHOUT having to have an initial (and time consuming) 3D wireframe.


1.- In a folder (with no spaces in the route) create a txt file as shown in the next figure:

2.- Start Geo Meshing and click on “FMT”. Select “Text File” option. Click “Open Points Cloud” and select the file you just created. Set the options as in the next figure:

3.- Click Mesh / Interpolate

4.- In Geo Meshing click the option “Load” and select the file with extension ”…_top.gmm”. Once loaded Click the “F” in the render area

5.- Under 3D surfaces menu select “3D polygonal excavation surface”

6.- Locate the mouse near (x,y) = (0,70) and click. You will see a red mark in the render area and the first coordinate appears in the “polygonal excavation” window, as shown in next figure

7.- Keep clicking clockwise to form a quarter of circle (aprox). You will see a series of blue marks in the render area and seven coordinates are displayed in the “polygonal excavation” window, as shown in next figure

8.- Complete coordinate #8 and #9 with (18,0,50) and (0,0,50)

9.- Change X coordinate of #1 to 0.0 and #7 to 18.

10.- Click “Open Mesh File” and select the file “…_top.gmm”

11.- Complete all “polygonal excavation” option as follow:

12.- Click Generate

(optional) Using the load option, load the file “…_top_exc.gmm” and you will see

Finally mesh the volume. Use the “3D meshing” window. Click the Open Bot. option and select the file “…_bot.gmm”. Write a file Name and provide a height of 1. The 3D Meshing window should look like

Finally, from FLAC3D, call the dat file “bath_tub.dat” and plot the zones. You will see a model like the one in the following figure:


This topic was modified 1 year ago by aarenas