We are fixing two small bugs related to parts colliding with Terrain water when they should not. The fix may impact some games.

The first is a bug where water does not react to Collision Groups. You can set the Terrain’s collision group, and if you have a part set to not collide with the Terrain’s group, it will still collide with water. We are fixing this so a group set to not collide with the Terrain’s group will ignore both the ground and the water.

It’s possible that your game is relying on this broken behavior unintentionally, where something is set to not collide with Terrain and its still floating. If you are explicitly relying on this behavior in your game, please let us know!

The other bug occurs where a part set to canCollide=false can still collide with water if listening for a touch event. This means you may have a floating structure that has non colliding parts with touch events that are contributing to buoyancy when they shouldn’t. We are fixing this so all non-colliding parts will not collide with water or impact buoyancy. You can disable the touch events on non-colliding parts to see how it should actually float.

We had this change activated for a bit this week then disabled it due to a game reporting issues. We want to give developers more time to make sure they won’t be affected.

You can find a handy example of both of these fixes impacting a game in this post from @opplo Terrain Water Breakage: CollisionGroups & Buoyancy

(cc @Tomarty for reporting)

The change has now been activated (Sept 3)