Clemantine, there are a couple different ways to get your elevation data into SU. A TIN like Gaieus suggests has worked well for me, let me know if you have trouble creating that in GIS and I'd be glad to help, send me a PM. You could also do contours. I haven't used the cloud.rb but based on what I know about LIDAR it's probably your best bet and worth the time to figure out.
What GIS software are you using?
How large is your study area? Large terrain models with a lot of detail can get unwieldy.
Eric