Can someone explain Swing 1/2 and Twist?


these constraints make no sens at all, are counter intuitive and never work the way I expect them to

how can I force an object to rotate on one axis only ?

why is it when I try to limit swing 1 & 2 in a particular angle, it does not work at all

why when I use Swing 1 or Twist, it just does exactly the same thing

where are the other constraints ? like hinge ?


To force object to rotate in one axis only, just leave one axis limited or free, lock the rest.

Let’s say you have a door on a hinge and it should sit at 15 degrees in relation to a wall. To do this, you have to turn constraint itself to face 15 degrees direction.
The other option is to enable drives/motors and set target direction there, but this is a different functionality - motors will actively produce force to keep constrained objects in specific positions.

Twist1, Twist 2 and Swing correspond to Roll, Yaw and Pitch (not specifically in this order). You can see in which axis constrain will work in editor - constraint root will have circles showing the arc of rotation.

Here is PhysX documentation on a subject:

6D constrain (joint) can be used to create any other type of constrain.

nice, thanks Ill check these up

As of UE4 4.25.3 :

Twist : X axis
Swing1 : Z Axis
Swing2 : Y axis

I believe they should name them x,y and z for easier manipulation.