meshing problems: How to control the triangles size and how to get the edges properly

Hello!

I would like to mesh a 3d model into Matlab using data from a STL file, and I am facing two troubles in doing so.

1/ I would like to control the triangles / faces size.

2/ I am getting extra edges which obviously should not be generated and do not fit the 3D model (see figure attached 'femur.png')

Note: I am using the codes provided in (https://www.mathworks.com/matlabcentral/answers/359154-how-to-extract-edges-of-a-whole-3d-plot-and-also-for-the-holes-in-it) and (https://www.mathworks.com/matlabcentral/fileexchange/22409-stl-file-reader)

Thank you and best regards!