Most game engines use Quaternions to represent actual rotation, while exposing euler angles as a user-friendly interface. This is because the order of rotation matters for euler angles, and could cause directional-lock (rotating without actually changing the direction of the transform)
CarneAsadaFry
Quaternions are super interesting! They were discovered by the mathematician William Rowan Hamilton. The story goes that he was trying to discover a 3d analog for complex numbers for years, but could never get multiplication to work (it has since been proved that this is actually impossible in some sense), until one day, in a stroke of genius while crossing a bridge, he realized he needed to consider 4d numbers instead. He went down below the bride and carved the multiplication rules into the stone. There's still a plaque there today and some mathematicians are said to have made pilgrimages there for inspiration.
After Hamilton discovered quaternions, he realized they lend themselves nicely to 3d calculations and heavily pushed for their usage, wanting them to be taught in schools. However, many mathematicians took issue with their unintuitiveness (Lord Kelvin call them "an unmixed evil"), and it's even said that some parts of Alice in Wonderland (Charles Dodgson aka Lewis Carroll was an Oxford mathematician) are references to quarternions (for instance, poking fun at their non-commutativity; more on that here: https://www.maa.org/external_archive/devlin/devlin_03_10.html).
Most game engines use Quaternions to represent actual rotation, while exposing euler angles as a user-friendly interface. This is because the order of rotation matters for euler angles, and could cause directional-lock (rotating without actually changing the direction of the transform)
Quaternions are super interesting! They were discovered by the mathematician William Rowan Hamilton. The story goes that he was trying to discover a 3d analog for complex numbers for years, but could never get multiplication to work (it has since been proved that this is actually impossible in some sense), until one day, in a stroke of genius while crossing a bridge, he realized he needed to consider 4d numbers instead. He went down below the bride and carved the multiplication rules into the stone. There's still a plaque there today and some mathematicians are said to have made pilgrimages there for inspiration.
After Hamilton discovered quaternions, he realized they lend themselves nicely to 3d calculations and heavily pushed for their usage, wanting them to be taught in schools. However, many mathematicians took issue with their unintuitiveness (Lord Kelvin call them "an unmixed evil"), and it's even said that some parts of Alice in Wonderland (Charles Dodgson aka Lewis Carroll was an Oxford mathematician) are references to quarternions (for instance, poking fun at their non-commutativity; more on that here: https://www.maa.org/external_archive/devlin/devlin_03_10.html).