[Paraview] Bad triangulation for Polygon

[Bob Anderson]

OK, I'll try again without the attachments...

 

For polygons with lobes, the tests I've done with ParaView don't give correct surface triangulation.

In the case where the object comes from my custom reader, using output->SetPolys(myCellsPtr); it produces a surface that doesn't stay within the polygon boundary, and applying the Delaunay2D filter to the polyline object (SamplePolygon1Cell.vtk) also 'blobbs' the polygon.

See links in earlier message -a correct surface triangulation (SamplePolySurface.jpg), and the ParaView result (PV_Delaunay2D_Polygon.jpg)

I'm currently doing my own triangulation using 'hgrd_src' routines from CodeProject, but if there is a better way to get the correct results within ParaView I'd be happy to try it.

 

Here is the VTK object (SamplePolygon1Cell.vtk):

# vtk DataFile Version 3.0

vtk output

ASCII

DATASET POLYDATA

POINTS 49 float

15.5517 43.6143 0 -3.2146 43.9618 0 -16.073 43.2667 0 

-26.4987 38.0539 0 -28.7576 31.4509 0 -21.9809 21.894 0 

-13.6403 22.4153 0 -5.99478 28.3232 0 2.51955 28.6707 0 

5.99478 21.5465 0 3.90965 10.0782 0 -5.4735 -0.347525 0 

-20.7646 0.69505 0 -38.1408 3.99652 0 -53.7793 6.77671 0 

-66.2902 3.47524 0 -70.2867 -3.30148 0 -74.8045 -15.9861 0 

-74.2832 -26.7593 0 -78.106 -44.1355 0 -63.51 -52.9974 0 

-50.1303 -50.0434 0 -44.7437 -41.3553 0 -49.609 -33.8836 0 

-50.8254 -24.1529 0 -39.5308 -21.894 0 -27.8888 -25.3692 0 

-20.5908 -32.4935 0 -15.5517 -38.5752 0 -4.95222 -48.6533 0 

15.7255 -50.391 0 33.2754 -49.3484 0 52.3892 -44.3093 0 

60.2085 -31.9722 0 60.3823 -21.894 0 54.6481 -14.4222 0 

44.7437 -11.2945 0 32.9279 -14.596 0 24.066 -21.199 0 

14.8566 -29.7133 0 5.12598 -30.7559 0 -1.12945 -23.1103 0 

0.0868797 -15.6386 0 7.03735 -13.901 0 20.7646 -9.20938 0 

33.2754 0.69505 0 42.8323 11.1208 0 39.7046 29.0182 0 

33.2754 39.7915 0 

LINES 1 51

50 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 0

 

Bob Anderson

MIRARCO Mining Innovation

Laurentian University

 



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