hrtask's Introduction

soup2ply

The aim of the task is to transform the mesh consisting of flat triangles from the 'soup of triangles' to the PLY format.

Soup of triangles

List of vertices, three subsequent values represent a 3D vertex, nine subsequent values represent a planar triangle in 3D. Vertices are not unique, can appear multiple times in the file.

-9.659780e-02 -1.969390e-02 1.874010e-02
-9.673700e-02 -2.205980e-02 1.878610e-02
-9.683260e-02 -2.207070e-02 2.881010e-02
-9.683260e-02 -2.207070e-02 2.881010e-02
-9.670800e-02 -1.968200e-02 2.873670e-02
-9.659780e-02 -1.969390e-02 1.874010e-02
-9.682140e-02 -2.478340e-02 1.883970e-02
-9.692880e-02 -2.477640e-02 2.884680e-02
-9.683260e-02 -2.207070e-02 2.881010e-02
...

PLY format

PLY separates the definition of unique vertices and an element field with indices to the vertex field, see http://paulbourke.net/dataformats/ply/ or https://en.wikipedia.org/wiki/PLY_(file_format).

ply
format ascii 1.0
element vertex XXX
property float x 
property float y
property float z
element face YYY
property list uchar int vertex_indices
end_header
-9.659780e-02 -1.969390e-02 1.874010e-02
-9.673700e-02 -2.205980e-02 1.878610e-02
-9.683260e-02 -2.207070e-02 2.881010e-02
...
3 0 1 2
3 2 1 3
...

XXX ... number of vertices

YYY ... number of faces