How to place single GPU particles at specified locations?

Yep, most LIDAR data is provided with some sort of classification in order to be able to filter the laser returns and only keep the ground (for DEM production and archaeological/micro-topographical detection).
A “good” classification is precise enough to filter low foliage, high foliage, rocks, constructions and such. So, indeed, I get how you could use this to improve foliage seeding algorithms.

I will upload the colored Besancon data tonight, I am very curious to see how shadow rendering would do with this dataset.

I will also have to read more carefully your last post, because I am not quite sure I understand everything !

By the way , do you think it’s possible to use what nvidia developed recently (see http://on-demand.gputechconf.com/gtc/2016/presentation/s6512-innfarn-yoo-massive-time-lapse-vr.pdf) and “hook it up” in some ways to the engine ?
I am in touch with them about this project, could be possible to make this happen with some help from their side.