Use for questions about using antenna modeling software to simulate an antenna system and determine its gain and radiation pattern.
The correct spelling in English-speaking countries outside the US is antenna-modelling.
With modeling software, you can determine the pattern, feed point impedance and even the SWR of your antenna system before cutting one piece of wire or one tube of aluminum. This can save an awful lot of tree and tower climbing.
Antenna modeling used to be the domain of scientists and engineers with very expensive antenna ranges covering acres and acres of land strewn with expensive equipment. However, with the proliferation of personal computers and affordable (even free) software, antenna modeling has become a popular amateur activity.