[Gmsh] Confining the mesh elements to a sphere given a 3D volume mesh

[Prithivirajan V]

Dear Gmsh users,

Let me explain my problem in detail :

I  do not have a geometry file for my model. I have a collection of .STL
files ( of a poly crystal obtain from DREAM 3D)


   1. With all the .STL files available , I made a 3D volume mesh using
   Gmsh. 3D volume mesh is shown below with exploded view of few individual
   volumes:

[image: Inline image 3]





*Now given the above 3D mesh , Would it be possible to confine the mesh to
a sphere ( with center x,y,z and radius R)  *


  I made an attempt to confine the mesh to a sphere but wasn't successful,
I tried to use the mesh refinement fields like attractor/threshold and ball
fields near the desired point , I got something like this. this picture was
obtained when I selected all the elements inside a sphere of radius R and
center x,y,z


[image: Inline image 4]


If I can confine all the elements protruding to a perfect sphere that would
be really helpful -Your help is greatly appreciated


A little more detail :

My final  objective is to create a  perfect spherical void inside the 3D
volume as shown above. This will be done by deleting all the elements of
figure 2.

2D analogy for my problem is depicted in the following figure:


[image: Inline image 5]



The first one is the fully dense mesh and at a point i need to create a
circle , delete all elements inside it and readjust the overall mesh to
obtain the right figure, I would like to remind that this is just for
explaining my problem , I have to deal with a 3D equivalent problem.


Thanks,

Prithivi
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