We started in the air, with pretty much every degree of freedom. We had two hovercrafts and a local multiplayer set up with guns. It did not go well. The ride was all over the place, there wasn’t enough visual context to anchor us in the world and being chased by an enemy in the distance was very vomit inducing, making the player constantly look in every direction other than forward.

We set out identifying as many instances where we felt sick. The game really has become a labor of love which we have spent a lot of physical pain working through. But don’t worry – it gets better. It turns out you want to give the player every reason to constantly look straight ahead in relation to their vehicle, which means making the vehicle extremely agile.

We realized we needed the player looking forwards and not providing much of a reason to look over their shoulder or behind. We realized we needed to restrict the player’s degree of freedom so that roll and pitch are mostly removed. We put the player on the ground which proved to be an instant hit and these things instantly reduced a lot of motion sickness. At that point, we started thinking multi-player would not work because of the chasing aspect so we continued with single-player in mind.

Motion sickness occurs when a player’s visuals don’t sync up with what their brain is expecting to happen. We have ended up using a PID controller in combination with the Unity physics engine to have tight control over the player’s motion. This acts as sort of a low/high pass filter on motion noise, meaning when a player is trying to get their VR legs in your game, not only is it done much quicker, but they retain them for longer. The motion is consistent and that way the player is able to build up a model of motion in their brain for predicting what is coming next – which leads to a much further reduced level of motion sickness.