Visual Preview creates QGraphicsItems for every platform location, capture on the ground, etc. For something like a LIDAR simulation with 10's of thousands of pulses, the tool gets way to bogged down with drawing the items.
The solution is to temporally animate the simulation so that only a small number of items need to be drawn at a time. Plus, the temporal animation will aid in understanding for the end user.
I experimented with a proof of concept last weekend that allows the user to animate the the collection. This allowed me to load up the LmAPD tutorial simulation (70,000 pulses) and look at it without a hitch. The animation was based on event index in my proof of concept, I just need to switch to time so it will deal with multiple instruments, multiple focal planes, bi-static scenarios, etc. I will get back to work on it this weekend.
Various improvements are checked in for 4.4.2 release.