Using UE4 Version 4.15.1 and Blueprint exclusively.
I’m making a VR demo using motion controllers where I have an object (Object A) set on a spline with two points (Point A, and Point B). The object is stationary but can move back and fourth between Point A and B when physics are applied to it but it cannot leave the spline. There is also an object attached via a Physics Constraint Actor (Object B) that the user should be able to grab, (Object B)'s position when grabbed is relevant and can be reset when released. When they do, (Object B) will pull the constrained actor (Object A) on the rail back and fourth.
The main issue I’m running across is having (Object A) move across the Spline.
I was able to get the object to move linearly across the spline by using the blueprint below, however this is a linear update and doesn’t include physics interaction. I’ll provide that below.
Adding some more information I’ve learned. The problem still persists but I’m getting closer. I’ve created this blueprint to update the object based on a float value between Point A and B on a curved spline. This is using the “Find Input Key Closest to World Location” and “Get Key Location At Time” to find a vector, then on the Event Tick it’s updating Object A to that location on the timeline.
The issue here is the object can still be pushed beyond the spline boundaries, but it will snap back on the spline once physics are no longer applied against the object. Additionally, turning off “Sweep” on “Set World Location” will help prevent the object from going off the spline path, but it will only stop it as fast as the event tick can update. The movement is also more jittery as it snaps to the closest location each frame. This is not desirable.