Sphere flatenning

[petrasvestartas]

Hi,

I am using command line interface.

For 2d flatenning I use texture coordinates to buid a mesh from out.obj.

For a unit sphere mesh how can I build mesh from texture coordinates since these are x and y values and there is no z coord?

I tried simple from polar to cartesian conversion but it wont work

                    p.X = 1 * Math.Sin(v.X) * Math.Cos(v.Y);
                    p.Y = 1 * Math.Sin(v.X) * Math.Sin(v.Y);
                    p.Z = 1 * Math.Cos(v.X);

[rohan-sawhney]

Hi @petrasvestartas, the spherical uv coordinates are mapped to the plane using the procedure described here: https://en.wikipedia.org/wiki/UV_mapping#Finding_UV_on_a_sphere. You could invert that, or probably the simplest thing to do would be to just to write out the 3d spherical coordinates by commenting out the conversion to the plane here: https://github.com/GeometryCollective/boundary-first-flattening/blob/e9bce6e0a7da5c12f5537e87a23ed6e94fdb2f47/mesh/src/MeshIO.cpp#L589

[petrasvestartas]

Hi,

Thank you for the answer.

Would it be possible to show how the inversion could be made to retrieve XYZ coordinates from MeshIO.cpp? Especially to get x and z coordinates.

I am using the command line and have very little knowledge of C++.

[petrasvestartas]

Is it mathematically possible to get back XYZ coordinates from UV spherical ones?

[rohan-sawhney]

Spherical positions are exported in place of the original mesh