The Kepler equation solver is the standard Newton iteration, which is ok until e gets larger. The actual N-body simulator in gravity engine allows for better or

The Kepler equation solver is the standard Newton iteration, which is ok until e gets larger. The actual N-body simulator in gravity engine allows for better orbits and the integrator is configurable (Hermite, Leapfrog) and easy to extend. Colwells book has LOTS on this subject too (https://www.willbell.com/MATH/mc12.htm https://www.willbell.com/MATH/mc12.htm) There are about 20 GE users so far, so it seems somewhat "niche". Offering an asset forces me to think a lot more about usability and documentation. I have recently added support for any solar system object and real world units - with tunable scaling. Not things I would have done if I was not making it an Asset. It's gratifying to get some uptake and the people who use it seem to like it. If you like Three Body stuff, checkout my iOS/Android three body app. LOTS of solutions to explore. (https://itunes.apple.com/us/app/threebody-lite/id951920756?mt=8/ https://itunes.apple.com/us/app/threebody-lite/id951920756?m... or https://play.google.com/store/apps/details?id=com.nbodyphysics.threebodylite&hl=en https://play.google.com/store/apps/details?id=com.nbodyphysi...)