Gravity causes movement to stick to objects

Development Programming & Scripting C++
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1

I have code that causes the actor to move, however enabling gravity causes it to stop moving whenever it lands on a surface. There is a solution here but for some reason a static mesh as a root has the physics grayed out so that isnt an option either. Any options at all?

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Is there a mesh assigned to the static mesh component?

I have code that causes the actor to move

So many things depend on the method used. Adding offset is so much different from simulating physics and is so different from a movement component.

Consider adding more details how the whole thing is supposed to behave.

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Yes, as the root component. I am moving by adding offset. I explained it very poorly. The actor is supposed to move side to side on the ground, it can move in midair, and when there is no gravity applied. When i add a collision box at the root instead of a mesh, to give it gravity it lands, bounces once, and sticks to the ground, completely unable to move for some reason. When i try to follow the solution, i cant enable simulate physics on the mesh. I am using the same mesh as the thread i linked, a 100x100x100 bsp brush cube, moving on the default platform.

Edit: I forgot the most obvious solution, add collision to the mesh. This is my second day learning c++ and i keep making incredibly dumb mistakes. Apologies.

Re-edit: Physics work, but its still getting stuck, with beveled collision, ccd, and an insane amount of solvers (100 each), Setting collision to sphere/capsule fixes it, but i still wonder if non-capsule/sphere objects can slide. Setting physics material to frictionless does not help.

4

You’re going to have a bad time.

If you’re moving a simulating body, you have 2 choices:

  • avoid using moving by offset / set location at all cost - a can of ugly worms that in no way meshes with simulation; a.k.a. not really a choice
  • use physics only - not so easy to control but the most realistic looking
  • use physics + movement component - works really well as you get to use movement input, easy to control but the movement component makes certain behaviours more rigid, predictable, non-physical. But it also offers additional goodies, like using navmesh for pathfinding.

Namely, in a Pawn:

image

The mesh is simulating physics and has (optional) gravity.

image
image840Ă—334 54.1 KB

This box is using the default box collision, efficient. You get superb collision detection (in most cases), and if you add a physical material to the mix, you get granular control over friction, restitution and more goodies.

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5

@Everynone, thank you for posting this answer! It was exactly what I needed! :slightly_smiling_face: I’m grateful to folks like you who take the time to help others.

In case it’s of interest to anyone, here’s how I applied the answer in code. Take this with a grain of salt as I’m still learning Unreal and C++.

–header–

UPROPERTY(EditDefaultsOnly, Category = “Input”)
class UFloatingPawnMovement* FloatingPawnMovementComponent;

–constructor–

FloatingPawnMovementComponent = CreateDefaultSubobject(TEXT(“Floating Pawn Movement Component”))

–move function–

void ATank::Move(const FInputActionValue& Value)
{
const FVector2D MovementVector2D = Value.Get();

// move forward-backward
const float Forward = MovementVector2D.Y;  //framerate independence handled automatically by AddInputVector
FloatingPawnMovementComponent->AddInputVector(GetActorForwardVector() * Forward);

// turn
const float Turn = MovementVector2D.X * GetWorld()->GetDeltaSeconds() * TurnRate;
const FRotator DeltaRotation(0.f, Turn, 0.f);
AddActorLocalRotation(DeltaRotation, false);

}

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6

AMEN.

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