[Peida]

Dear all,
Nice to see you guys, I’m a new user and I have a terrain .txt file. I would like to mesh that.

I used this terrain meshing tutorial: tutorials/mesh/moveDyamicMesh/SnakeRiverCanyon.

Firstly, I used MeshLab to convert my .txt file (3 colume, x-coordinate, y-coordinate and height) into .stl file, then I modified the tutorial to generate the mesh.

But it seems that the mesh is weird with sharp edge, and OF shows that the geometry check is failed.

Here is my result and my code.

Thanks a lot and look forward to you reply lol

(Result when I run SnakeRiverCanyon, show Time=1 for example)
Time = 1
surfaceDisplacement : on patch minZ did not project 3 out of 40401 points.
GAMG: Solving for cellDisplacementx, Initial residual = 1, Final residual = 8.64577e-09, No Iterations 9
GAMG: Solving for cellDisplacementy, Initial residual = 1, Final residual = 3.93566e-09, No Iterations 10
GAMG: Solving for cellDisplacementz, Initial residual = 1, Final residual = 7.4888e-09, No Iterations 8
Point usage OK.
Upper triangular ordering OK.
Topological cell zip-up check OK.
Face vertices OK.
Face-face connectivity OK.
Mesh topology OK.
Boundary openness (-8.37097e-19 -3.83493e-19 -3.45847e-15) OK.
***High aspect ratio cells found, Max aspect ratio: 1.20381e+106, number of cells 183
Minimum face area = 0.00609877. Maximum face area = 8965.54. Face area magnitudes OK.
***Zero or negative cell volume detected. Minimum negative volume: -5266.04, Number of negative volume cells: 183
Mesh non-orthogonality Max: 179.979 average: 3.31798
*Number of severely non-orthogonal (> 70 degrees) faces: 2268.
***Number of non-orthogonality errors: 603.
***Error in face pyramids: 1449 faces are incorrectly oriented.
***Max skewness = 584.992, 56 highly skew faces detected which may impair the quality of the results
Failed 5 mesh geometry checks.
Failed 1 mesh checks.
ExecutionTime = 14.58 s ClockTime = 15 s

[Peida]

I feel like my problem results from .stl file.

Firstly, I generate my .stl file from XYZ.file (x coordinate, y coordinate and height) by Meshlab . Then I run my case modified by Snakeriver and the result is not good (the bottom of block moves to stl surface but sharp edge appears.)

so I try to convert .stl file by Matlab, the code shows below:

[X,Y,Z]=textread('AcrossRiver.txt','%f %f %f');

% triangulate in xy
T = delaunay(X,Y);
% create triangulation in 3d
tri = triangulation(T,X,Y,Z);
% plot
patch('Faces',tri.ConnectivityList,'Vertices',tri. Points,'FaceColor','red');
% now save
stlwrite(tri,'jisadas.stl');

The result gets better, the show time of the sharp edge delays. But it still shows up.

[Peida]

So I wonder that if there is anyway to generate high-quality .stl file.
And here is my .stl file
Oops, it‘s too big...

[HPE]

- if you have CAD file of the geometry, instead of STL, use SALOME or Blender to create surface mesh, i.e. STL

[Peida]

Originally Posted by HPE

- if you have CAD file of the geometry, instead of STL, use SALOME or Blender to create surface mesh, i.e. STL

Dear HPE,

Thanks for your suggestion. I have CAD and I wonder that what is SALOME or Blender, utilities in OF?

And I have figured out my problem:

If you use moveDynamic turorial, you should care the ratio of the xyz resolution. If z-resolution is too low, the result will get bad.

Peida

[TomS]

Glad you managed to resolve your issues, Peida.

The STL attached was generated using a combination of SALOME and MeshLAB. It was then used for a littoral flow study using OpenFOAM:

https://www.mts-cfd.com/loch-erisort

Best wishes,

Tom