Godot: Run the project for a few seconds and the collision will fail

[haizhou37]

Godot version:
godot3.0.6or3.1alpha1

OS/device including version:
manjaro 17.1.12 x64
Intel® Core™ i3-2350M CPU @ 2.30GHz × 4
Intel® Sandybridge Mobile
3.8 GiB

Issue description:
Run the project for a few seconds and the collision will fail in godot3.0.6or3.1alpha。If you don't wait and hit it right now,there's no problem with the collision.

Steps to reproduce:
Create a rigid body, wait a few seconds, and control another object with a collision body to hit it. The collision will fail.

Minimal reproduction project:
Test.zip

[bojidar-bg]

Tested the project, seems like a problem when a KinematicBody gets positioned (via translated) inside a RigidBody which is sleeping. I'm not sure this is a bug.

@haizhou37 You should use move_and_collide or move_and_slide when moving a KinematicBody, because translate does not update it or other physics objects properly (it acts as if the KinematicBody was teleported, not moved).

Additionally, try to put physics related code in _physics_process, not _process (though this did not change the behaviour of the sample project).

Finally, if a RigidBody misbehaves after some time, you can always try to uncheck its "Can Sleep" property, but mind that sleeping is a performance optimization, so it should be disabled with care.

[NewNodeGames]

You should use move_and_collide or move_and_slide when moving a KinematicBody, because translate does not update it or other physics objects properly

This is the key

[bojidar-bg]

@NewNodeGames That's why I put it first, before the other suggestions.

[aaronfranke]

Perhaps there should be a warning if someone calls translate on a PhysicsBody.

[haizhou37]

Tested the project, seems like a problem when a KinematicBody gets positioned (via translated) inside a RigidBody which is sleeping. I'm not sure this is a bug.

@haizhou37 You should use move_and_collide or move_and_slide when moving a KinematicBody, because translate does not update it or other physics objects properly (it acts as if the KinematicBody was teleported, not moved).

Additionally, try to put physics related code in _physics_process, not _process (though this did not change the behaviour of the sample project).

Finally, if a RigidBody misbehaves after some time, you can always try to uncheck its "Can Sleep" property, but mind that sleeping is a performance optimization, so it should be disabled with care.

Thank you. You're right. Additionally, if I try to turn off the can sleep, cube won't lose the collision

There's also a question outside the theme.In my project, objects need to apply physical force based on the player's keyboard input. According to general development experience, the game logic and input detection are run in _ process, and the force is applied in _ physics_process, so how should this be separated in programming to achieve the effect mentioned at the beginning?

[Zireael07]

Your latest question belongs on the forum, Discord or the Q&A site - this tracker is for actual bugs in Godot itself.