Answers for "Is there a reliable replacement for the Quaternion math in blueprints?"
https://answers.unrealengine.com/questions/17733/quaternion-in-blueprints.html
The latest answers for the question "Is there a reliable replacement for the Quaternion math in blueprints?"Answer by Osakanone
https://answers.unrealengine.com/answers/830481/view.html
![alt text][1]
[1]: https://i.ytimg.com/vi/YRCzEqkCoiM/maxresdefault.jpg
https://www.unrealengine.com/marketplace/blueprint-quaternion-library
When composing a quaternion from two vectors, the first vector is the master vector which the new rotation will do its very best to adhere to! The second is the slave vector, which will supply all other rotation information. For example, by using the surface normal as the Z vector and forward as X, you can align a character with a surface using Compose from ZX!Fri, 21 Sep 2018 17:26:40 GMTOsakanoneAnswer by mightyenigma
https://answers.unrealengine.com/answers/699838/view.html
Okay so I think what JamesG (https://answers.unrealengine.com/users/98/jamesg.html) was saying is that although Quats are not a Blueprint variable type, you can feed Euler-based Rotators into certain math functions such as CombineRotators and NegateRotator, and it will calculate them using Quaternions to output a new transformed Euler-based Rotator that didn't get gimbal-locked (did I understand that correctly?)
He says you can store rotations in a Transform, which stores them internally as Quats, and I think you feed that Euler angles too. So basically in Blueprint it sounds like you cannot create or edit Quaternions, but you CAN get equivalent Euler angles without gimbal lock issues by doing all your rotator transformations via the math nodes that use Quaternions internally. You input Eulers to them and they output Eulers, but they use Quats to calculate so they should avoid gimbal lock. It's blackboxed but you can used it to get the same results. Did I understand that correctly?Fri, 25 Aug 2017 16:46:25 GMTmightyenigmaAnswer by Bartosz Kamol Kamiński
https://answers.unrealengine.com/answers/666373/view.html
Bump! I need quaternions too.Fri, 04 Aug 2017 07:59:56 GMTBartosz Kamol KamińskiAnswer by Evols
https://answers.unrealengine.com/answers/442130/view.html
Hello ! Blueprint node "Combine Rotators" is in reality making a quaternion rotation !
Here is the proof : When you call this node, it converts both rotators to Quaternions (FQuat), multiplies them, and returns the result as a Rotator !
![UE4 Quaternions][1]
Hope it helped ;)
[1]: /storage/temp/96171-ue4+combine+rot.pngSun, 26 Jun 2016 21:06:46 GMTEvolsAnswer by JamesG
https://answers.unrealengine.com/answers/17877/view.html
We don't plan to add Quaternion support to Blueprints because they are quite complicated to enter and create from components, whereas Euler angles (Rotator) make quite a lot of sense to break apart and put back together. We did however expose several maths functions which convert to quaternion under the covers (e.g. 'Combine Rotators' and 'Negate Rotator' nodes). You can also use a Transform which stores the rotation as a quaternion internally.Tue, 25 Mar 2014 10:02:07 GMTJamesGAnswer by Roel
https://answers.unrealengine.com/answers/17857/view.html
I think in the background the Rotator (sometimes in blueprint referred to as Rot) is in the background actually a Quaternion, but since most people don't feel like doing math with Quaternions, the only show Euler angles. Even if you break a Rotator it will output the Euler.
So in short, try using the Rotator functionality for anything you want to do with rotations.Tue, 25 Mar 2014 09:05:56 GMTRoel