Anti-aliasing

By default, FlightGear will not use anti-aliasing during the simulation. This results in incorrect rendering of sharp straight lines and very small objects. In order to correct this, you can apply the anti-aliasing function; however, this will slow down rendering and is not guaranteed to work on all graphics cards.

Example

Anti-aliasing disabled	Anti-aliasing enabled

How to set anti-aliasing

Command line

When starting FlightGear via the command line, add the following two arguments:

--prop:/sim/rendering/multi-sample-buffers=true
--prop:/sim/rendering/multi-samples=4

FGRun

Setting anti-aliasing in FGrun

When you use FGRun, add these commands under Advanced > Properties.

Qt Launcher

If you are using the Integrated_Qt5_Launcher, then you can easily enable anti-aliasing by toggling the "Enable Mutli-sample anti-aliasing" option from "Settings" tab.

Rembrandt

Anti-aliasing does not work with Rembrandt enabled due to GLSL limitations, but some graphics cards have hardware anti-aliasing which may work.

Options

If preferred, you can choose another value for the number of samples. The number has to be greater than 1. The greater the number of samples, the slower rendering will be.

Thanks to fredb for publishing this information on the FlightGear forum.