Particles density clipped by camera field of view

In the environment modelling is useful to use particles to instance grass blades, bushes, trees etc… but for large environment the memory usage will reach fast unmanagable limits.

This problem is the same for all the scatter plugin and some of these have found the solution to clip the density by field of view.

A video about this feature of ForestPack for 3dsmax by Itoo Software can explain more than thousands words.

Has someone ever tried to replicate something similar?

Is it possible to do?

Any ideas??

Thanks in advance