Simul Support ExchangeCategory: Water"Generate waves" unusable with ships
Martin Gre?ák asked 1 month ago

^video showing the issue
I could be doing something wrong but i am unable to set up wave grid and generate waves in manner for ships to use it. Waves are generated when ship is dropped from height and “probes” impact/submerge into water. However moving ship on surface using unreal default propulsion system called “THRUSTER” has no effect on generating waves.

  • 4 probes set along waterline (red part of ship hull), front back and one on each side
  • probe type “physics”, generate waves “enabled”, sphere radius “700”
  • mass of mesh – 3700.0 kg
  • thruster initial force “30000.0” (barely moving) “5930000.0” (decent speed)
  • beaufort scale = 0 (for better visibility of generated waves)

Tried using thruster as “component” for the mesh having trueskywaterbuoyancy or a child (attached in hierarchy) of mesh with no improvement.
Increasing thruster force make ship tilt front/back which make a tiny waves however after few seconds ship stabilize and once again make no waves while sailing on water.
Per suggestion on slack of using “source probes” i have to oppose that this doesnt work for use case at all. Source probes generate waves which affect ship movement itself as they go to all directions including towards ship itself. (in short physics probes react to source probes of same object)
Please advice what type of propulsion/moving system is recommended to work with wave grid.
(newest available version of truesky 4.2, unreal 4.25.4)

Martin Gre?ák replied 1 month ago

Forgot to mention that probes are set on water level so their center is directly on surface. Ship weight is balanced to float exactly like this, waterline of ship being in line with water surface.
I tried submerging probes with exaugurated ship weight with no results. I tried it lift up ship by reducing weight so that probes are barely touching water with no results.

Martin Gre?ák replied 4 weeks ago

Also forgot to mention, whole effort was to achieve “ship wake” using this feature.
If user drag object (with wave probes) during running simulation at viewport manually by mouse, ship produce absolutely beautiful wake… so i only assumed this is “ment” to work.

1 Answers
Best Answer
Chris_Simul Staff answered 4 weeks ago

Hi Martin – This is also something we are aware of and are working to get alleviated. I have again update the bug card with the extra information you have provided – I do however have a workaround for the current system which may prove useful. I have created a brief video showcasing this in action (sadly did not have a boat mesh at hand). This solution is not ideal as mentioned, however should see you over until we get a robust fix in place.
Example Video can be found here
Fix – Add a short delay to your applied force’s. Even if its only slight, meaning you don’t notice that the movement is essentially stuttered, however allows for the water probes to act correctly.
An artifact of this (as you can see within the video) – is that the boat travels slightly slower, however some tweaks to values could potentially solve the issue temporarily.

Martin Gre?ák replied 4 weeks ago

Thank you Chris! And thank you for taking time to make video too.
The workaround works for now. 🙂

Is there any place i could follow progress on more permanent solution ? (known issues/feature list)

I noticed that ship tend to dive and raise a lot periodically as it travel, my guess is the physics probes have to “jump over” the wake. Ship kinda tripping over its own wake. (damping may improve it tho)

Chris_Simul Staff replied 4 weeks ago

No problem 🙂 its the least I can do.
Currently we don’t have anywhere to track progress on bugs – I will add it onto the known Issues list and update that once a new update has been pushed. We are looking into potential solutions for showcasing our roadmap and what we are currently working on.
Sounds like that’s most likely the case, or the force being applied in a staggered way is almost bouncing it in and out of the water – Not sure on a test I could set up to look at it, potentially “hacky” solution off the top of my head would be applying a slight downward force could work, or could make the issue more amplified or to reduce the time on the delay to attempt to make the force be more consistent and not cause the bouncing? Damping may be the way forward though as you mentioned.