Hi,

I would like to create a box of certain size (let say 5um x 5um x 5um) that efficiently packs a certain number of non-overlapping Spheres and another box that packs a number of non-overlapping Shells. The radius of the Spheres and the inner and outer radii of the shells are random variable drown from Gaussian distribution with certain mean and STD. Below is a picture to illustrate what I am aiming for (was done using molecular dynamics packing code developed by M. Skoge )

I tried the following structure groups: 1- Gaussian random particle distribution. 2- Linear random particle distribution and 3- Uniform random particle distribution. The problem is that these three have very low packing efficiency. By that I mean, there are so many spacing between the spheres (picture below). They are not as dense as the picture above. Which is very critical to me. Also, the radius is just a random number between r_min and r_max. Finally, they donâ€™t give you the option to simulate shells or any other nano objects but spheres.

I guess my questions are: 1- How to make the radii of the sphere follow Gaussian distribution?

2- How to optimize the packing so that we can maximize the density with no gaps?

3- How to simulate random shell particles and not just spheres?

Thx