4.27 Water buoyancy not working?

Created a waterbody. Created a BP for my object and added buoyancy there. Created 4 pontoons. Object just sinks.

Tried using example object BP_BuoyancyExample and it sinks too. What could I do wrong?

Could be a number of things. Make sure your object is placed way above the water surface. Radi of pontoons shouldn’t be too small. Maybe adjust dampening in the buoyancy settings and verify your object isn’t too heavy.

I’ve found out that FOR SOME REASON Auto Activate checkbox was not checked in both my object and example


Hi, have the same problem. Could you tell me how to activate this? New in unreal

Thanks for that! Works now! Was totally confused…

@ghost.grl You have to select the Buoyancy component in the Actor and under Activation make sure the checkbox Auto Activate is checked.


Working fine, thank you guys!

I have a similar problem but in my case auto activate in buoyancy component did not work . I tried to modify buoyancy coeff. increasing it to without any effect. btw the object mass i set to 8 (kg?). Pontons radi set to 10 (but using 100 also does not work).

The only major difference between my code and many example I see is that I’m using a pawn and not an actor … but this should not be a problem.

I tried also to use WaterTestMap in Water Plugin content folder using BP_BuoyancyExample but it just sinks.

I tried on 4.26.2 using Water plugin contents and it seems to works but if I create a simple cube with buoyancy (in the same level) it sinks all the times… the only way to make it work is to use EditorCube as static mesh.

I cannot understand where’s the fault but it sounds like a big-beautiful-bug…

Good work

It looks like from another thread that you can only have a maximum of two pontoons on the simple cube. I’ve found the same thing in my experimentation.

To test this, I used the OnWaterEnteredDelegate function of the Buoyancy component to check what force was being applied to the pontoon when it entered the water. If you split the output pin of that delegate function, you’ll see the vector for the force - then just print that out.

When I had more than two pontoons on the simple cube, I would have 0, 0, 0 as the force. But with two, it would show a force on the pontoons.