Why does a simple ball rolling on a flat surface have strange bounces in unreal engine 5.3?

[Elvisa0023]

https://youtu.be/P12sUZAyC6c

This example only has a simple ball Actor, rolling over a flat terrain, but the ball always has strange bounces and is a strange impulse in all directions.I only gave the sphere component a horizontal impulse in the horizontal direction, and it should just roll against the ground instead of having weird bounces.This situation is completely random.As like the ball had hit something on a flat surface, But the LandScape is flat.
Same level, same landscape, same ball, but its rolling in 5.2 is normal. I wonder if this is a Bug in UE5.3? Or do I need to do something else to adapt to 5.3?

[ClockworkOcean]

Have you tried it with a better ball?

If this is the default sphere, it will be ‘wobbly’.

You can make a decent sphere in the modelling tools ( SHIFT5 ).

[Elvisa0023]

I tried the engine’s built-in Sphere Mesh, but it also bounced inexplicably as it rolled across a flat surface.

[ClockworkOcean]

That’s what I’m saying, it’s not smooth enough.

Try making one with these settings

( and work your way down, this my be a bit much ).

One on the right is the engine sphere, look at the jaggies

[Elvisa0023]

And the collisions of components whose physics simulation is enabled cannot be set to complex collisions

[Elvisa0023]

Let me try

[Elvisa0023]

thank you for replay!
I tried you suggested, but I can’t use complex collisions when enable the physics simulation, I can still only add a simple sphere collision, so it will still have a strange bounce on the plane.

[ClockworkOcean]

Darn…

I have done almost exactly this before. ( can’t quite recall what happened… )

I think if you add the simple collision to your sphere, it will work…

[Elvisa0023]

Now I’m using a simple sphere collision, and it behaves just like the video I posted earlier

[ClockworkOcean]

I tried looking for my previous solution, can’t find it…

I’m waiting for my brain to spring into action…

[Elvisa0023]

Thank you very much indeed, I am still searching the Internet for any possible solution

[ClockworkOcean]

Did you try CCD?

[Elvisa0023]

Yes,I tried.it didn’t work

[ClockworkOcean]

Did you try tweaking

Rolling ball jumps on flat surface

As of 4.23 they do const float RestOffset = ComputeRestOffset(Elem); const float ContactOffset = ComputeContactOffset(Geom) + RestOffset; VisitorFunc(Elem, Geom, PLocalPose, ContactOffset, RestOffset); It seems like each Elem (Body Element?) has its own RestOffset but I see no way to edit that in editor but maybe it takes it from min/max contact offsets? In which case this should be working as it did before but even in 4.23 my physics isn’t as stable as it …

Not what I did before, but…

[Elvisa0023]

• I tried that, too
  
  
• But it didn’t work
• Thank you so much for your continued advice!
• I will also look into other solution.

[ClockworkOcean]

This is what I was looking for

Smooth movement of the sphere

Alas, this sphere cannot be used for physical simulations. When I start the game, it just hangs in the air. My scope is pretty detailed. Also, I suspect that it may be the collision sphere, it looks too low poly. UE sphere in air: [image] My Sphere: [image] Collision sphere: [image] Is there a way to subdivide the collision sphere?

maybe it’s how you’re coding the movement?

[Elvisa0023]

• Hey, brother.After I tried to reduce the Min Contact offset and Max Contact offset values and increase the Contact Offset Multiplier, the stability of the rolling state was much better!
  This seems to be a viable adjustment, and I have now increased the Offset Multiplier to 10, almost no strange bounces occur when rolling on a flat surface!
• Thank you very much for your advice! You’re the savior!

[ClockworkOcean]

Excellent