Tee-riffic Golf

This is likely the most complex system I contributed to this project.

Because of the way physics engines work, at least as it pertains to Unreal Engine 4, spherical objects will roll forever on a flat surface, unless acted upon by linear damping, for example.

To solve this, I developed a custom system that takes the ball’s speed at any given time and, if below a certain threshold and provided the ball is on flat ground, will start to exponentially increase the linear and angular damping on the ball until it comes to a stop.

This is a tick calculation, i.e.: it is called every tick. Here’s how it looks in blueprint: 

If the ball is moving slower than the threshold, the “Freeze Ball” event is called once, which will secure the ball in place. If it is above the threshold, the ball must be moving, so the “Slow Down Ball” event is called. 

Here’s a look at the “Freeze Ball” function, which is called when the ball is “practically stopped”: 

It very simply sets the linear and angular velocity to 0. Bear in mind this is called every tick, so it will do this continually (until the ball goes back over the threshold, hence the extra velocity check).

And here’s a look at the “Slow Down Ball” event, called whenever the ball is moving:

Part 1 of 3: 

Firstly, it checks whether the ball is below 250 units of velocity, and if it’s on flat ground. If it's not, there is no need to apply additional damping, so the default “moving” damping values are applied instead, as follows:

Part 2 of 3: 

You can see above – given the ball is not inside a “damping modifier” volume (i.e.: tall grass, or in a melted state), the linear and angular damping values are set to 0.5 and 0.1 respectively. Of course, if they indeed are in those volumes, the damping modifier is applied on top of the damping defaults.

Part 3 of 3: