Without getting into too much detail now (I’m running out of time today) but you can get Lidar data into CityEngine with a bit of work, read on….
Basically you convert your LAS data to a multipoint file then convert from multipart to singlepart (in ArcGIS) and import the point data into CityEngine. (was that the worlds shortest workflow?!)
Now CityEngine does support points, it imports this but converts it into little polygon squares. These squares can then have rules run on them, normally I would insert trees on 2D point data, but that would look odd if I did it on a point cloud.
A word of warning point: clouds turn into massive numbers of polygons, you need to bare this in mind when working. CityEngine handles it okay but the export can be very slow…