unigine sim engine has the worst documentation i've ever seen. it was written in bad english, occasionally did not follow a word convention (i.e. functions doing analogous work used different keywords), most items were just reiterations of function names (made up example for clarification: getAngularVelocity(): gets angular velocity...). i had to use it for my first ever job, and had to learn in from scratch, mostly by trial and error. it's been months since i switched jobs, and they were rolling a version 2 when i left, i hope they improved on their docs.