How to create mesh from coordinates

Hi,

I have a 3D object (as shown in figure) defined entirely by x,y,z coordinates. Below shows the plot using scatter3().

I do not have the triangulation information.

My ultimate goal is to convert it to an .*stl file. How do I mesh it? delaunay(x,y,z) is giving something like this which is not correct.

Do I need some kind of algorithm to mesh it ?

Or else can I convert the coordinates to a .ply file to use meshlab to mesh it ? I don't know how to convert. Since this is a closed figure meshgrid() etc. are not working.

Thank you for the help.

Answer 1

[Kaustubh Tiwarekar]

I know its late. Bu8t this question needs a better answe.

Try referin to this link

https://in.mathworks.com/matlabcentral/fileexchange/63731-surface-reconstruction-from-scattered-points-cloud-open-surfaces

[Viraj Gandhi]

Thank you so much!! It saved a ton of my time!

Answer 2

[Walter Roberson]

If you have R2014b or later consider using boundary() to generate an outside hull.

[sumana]

Hi,

Thank you for the answer. But it does not work as I want it to. I got the below figure.

It is connecting many unnecessary points. Same with alphashape().

Could you suggest some algorithm or any other method ? How can I convert it to a pointcloud file ? Or could you provide an example with an arbitrary closed 3D shape, say a sphere?

Thank you

[sumana]

This is what I got using alphashape (), which is close but there is a hole in the middle.

Note: This object was first generated in geodetic coordinates and then converted to spherical.

[sumana]

Another view of it.

[Walter Roberson]

pc = pointCloud( [x(:), y(:), z(:)] );
pcwrite(pc, 'OutputFileName.ply');

This requires the Computer Vision Toolbox.