# Structured mesh in gmsh without Extrude function

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January 5, 2010, 15:24
Structured mesh in gmsh without Extrude function
#1
Senior Member

Eric Nutsch
Join Date: Sep 2009
Location: Eugene, Oregon USA
Posts: 113
Rep Power: 9
Hey everyone,

I have had good luck meshing tetras and prisms with gmsh. However now I am wanting to created a structured hex mesh.

Here is what I currently can do. It requires two extrude functions and can only be controlled by the first parameter:

______________________________________
Point(1) = {0,0,0,0.1};
Point(2) = {1,0.2,0,0.1};
Point(3) = {2,0,0,0.1};
Spline(1) = {1,2,3} ;

Extrude {0,1,0} {
Line{1}; Layers{5}; Recombine;
}
Extrude {0,0,.1} {
Surface{5}; Layers{1}; Recombine;
}

______________________________________

Here is what I want to do. This shape requires the mesh to be controlled by two parameters, and allows you to do much much more with it. Is it possible to do this?

______________________________________
Point(1) = {0,0,0,0.1};
Point(2) = {1,0.2,0,0.1};
Point(3) = {2,0,0,0.1};
Spline(1) = {1,2,3} ;

Point(4) = {-.5,1,0,0.1};
Point(5) = {1,1.2,0,0.1};
Point(6) = {2.5,1,0,0.1};
Spline(2) = {4,5,6} ;

Line(3)={1,4};
Line(4)={3,6};

Line Loop(5) = {1,4,-2,-3} ;
Plane Surface(6) = {5}

______________________________________

Attached Images
 CanMesh.jpg (41.0 KB, 1247 views) WantToMesh.jpg (12.8 KB, 1210 views)

January 6, 2010, 19:38
Got it to work!
#2
Senior Member

Eric Nutsch
Join Date: Sep 2009
Location: Eugene, Oregon USA
Posts: 113
Rep Power: 9
Persistence is victorious again...

A big thanks to dolfyn.net or I may never have figured it out:

Here is my script:
Code:
```// Kudos to dolfyn for an awesome tutorial
// http://www.dolfyn.net/dolfyn/gmsh/tutorial06.html

Point(1) = {0,0,0,0.1};
Point(2) = {1,0.2,0,0.1};
Point(3) = {2,0,0,0.1};
Spline(1) = {1,2,3} ;

Point(4) = {-0.5,1,0,0.1};
Point(5) = {1,1.2,0,0.1};
Point(6) = {2.5,1,0,0.1};
Spline(2) = {4,5,6} ;

Line(3)={1,4};
Line(4)={3,6};

Line Loop(1) = {1,4,-2,-3} ;
Plane Surface(1) = {1};

// Tell Gmsh how many cells you want per edge
Transfinite Line{3,4} = 10;
Transfinite Line{1,2} = 15;

// Tell Gmsh what the corner points are(going clockwise or counter-clockwise):
Transfinite Surface{1} = {1,3,6,4};

// Recombine the triangles into quads:
Recombine Surface{1};

// Havent tested this yet, but doesnt seem to hurt:
Mesh.Smoothing = 100;

// Extrued for a psudo 2D mesh :)
Extrude {0,0,0.15} {Surface{1}; Layers{1}; Recombine; }```
Attached Images
 HexWorks.jpg (42.5 KB, 1226 views)

 December 6, 2013, 08:52 structured mesh: transfinite surface with more than 6 corners #3 New Member   Join Date: Dec 2013 Posts: 3 Rep Power: 5 Hello, I need to create a mesh in a wind blade for my phd. I want to use hex element with structured mesh. I will get the geometry in a .stp file (see the attach please) so I can not interfere in the geometry. I merge the stp with a scrip (see the attach please) to recombine and transfinite but I have problems with the surface which has more than 5 corners.... the files are in this link https://dl.dropboxusercontent.com/u/...RightBlade.zip Any ideas please? binband likes this.

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