how to use move_and_slide on a rotating platform?

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how to use move_and_slide on a rotating platform?

icqqq

I want to achieve a character can follow a rotating platform to move. However I found move_and_slide do the job but is not perfect. Somehow when time moves, the position of kinematic character will shift.

So how to solve it?

My code in kinematic body:

vel = Vector3() func _physics_process(delta): vel.y += g*delta vel = move_and_slide(vel, Vector3(0, 1, 0))

My rotating platform is a rigidbody in kinematic mode and rotated by animation player

Thanks!

please find my project in the link: https://drive.google.com/file/d/19mSzlSlZkkp7AuoEKnE0yudV5-kn47r8/view?usp=sharing

rjoshua

Just a question, in the ready function do you write the following? func _ready(): set_physics_process(true)

I say it becase, in the example that you upload, it was not.

icqqq

@rjoshua said: Just a question, in the ready function do you write the following? func _ready(): set_physics_process(true)

I say it becase, in the example that you upload, it was not.

I think in Godot 3, you don't need to explicitly call set_physics_process(true) And if you run my project, the kinematic body do follow the platform rotate, which means the _physics_process is running. However, the body will shift and finally move out of the platform.

icqqq

@rjoshua said: Just a question, in the ready function do you write the following? func _ready(): set_physics_process(true)

I say it becase, in the example that you upload, it was not.

I have tested to add the set_physics_process(true) in _ready() but the result is the same...no improvement.

Megalomaniak

Sounds like: https://en.wikipedia.org/wiki/Acceleration#Tangential_and_centripetal_acceleration https://en.wikipedia.org/wiki/Acceleration#Circular_motion

icqqq

@Megalomaniak said: Sounds like: https://en.wikipedia.org/wiki/Acceleration#Tangential_and_centripetal_acceleration https://en.wikipedia.org/wiki/Acceleration#Circular_motion

So you mean I cannot simply use move_and_slide, but I need to calculate the angular velocity myself?

Megalomaniak

I mean if you place something on top of a rotating object such as a turn table it experiences centripetal acceleration(because friction).

@icqqq said:

However, the body will shift and finally move out of the platform.

So in other words add/raise friction, also might help to lower objects pivot point or whatever determines the center of mass. Also, raise mass or gravity. Plenty of ways to cheat against physics in a game engine.