The result of my computational simulation is a (time-dependent) system of large number (~100k) of moving particles in a confined space. Each particle has its own Cartesian coordinates as well as a weight ($w$) in the form of $(x_i,y_i,z_i;w_i)$.

I'm looking for a software/app/package to create a snapshot of the 3D spatial density map of these particles. (something like this). Like you see in this figure, the particles are not going to be displayed individually, but only a transparent cloud will be drawn whose local intensity is proportional with the local number of particles.

The final goal is to create a movie of the changing 3D spatial density with time.
So far, I have tried R, Matlab, Origin, and ImageJ. But no success!

Thank you for your help!