Physics controlled Actor behaves differently if possessed

[twinflyer]

I have posted this already on the unreal answerhub, as well as in the unreal engine IRC but so far nobody could help me with this.

The following is taken from my answerhub post which you can find here.

I’m trying to get a vehicle to move very arcady by using a simple box as the body and applying forces based on wheel positions, ground properties (mostly friction), and of course player inputs.

So far I’m quite happy with the results, driving around is fun and it works to a certain degree.

The Vehicle is based on a custom Pawn (AVehiclePawn.h /.cpp) which is controlled by the player directly for now (I want to use a playercontroller once this problem is fixed). It has a spring arm and a camera attached. Most of the magic happens in AVehiclePawn.cpp where I do raycasts and some math to achieve the desired result by adding forces at certain locations. The vehicle behaves correct as long as it’s not possessed by a player.

Once it’s possessed by a player (in my case by setting Auto Possess Player to Player 0) the vehicles rotation starts acting weird. It looks like there is a very high angular damping value set. The rotation just feels like the vehicle is surrounded by jelly. For some reason the linear velocity is not influenced at all.

I have no Idea where this comes from. Maybe this can be fixed by a custom MovementComponent or a custom PlayerController. I browsed the Source Code but I could not find anything which might influence pawn rotation. The effect is kinda good gameplay wise but it’s way to strong and I’d like to control it myself.

To show the described behavior I have uploaded a short video which demonstrates whats going on at the moment:

• the black box is the vehicle itself
• the white lines below the vehicle represent the raycasts for each wheel
• the green lines above the vehicle represent the UPWARDS force which are added to the box by each individual wheel
• the red lines above the vehicle represent a DOWNWARDS force added to the vehicle (box) by the wheels

- YouTube

Controlling the Vehicle from the level Blueprint gives the desired result, but thats not a permanent solution.
I’m not using any custom MovementComponents or PlayerControllers for now. As I mentioned in my answerhub post I think this could solve the problem but I have no idea on where to start.
I hope someone can help me with that. I want the vehicle to behave the way its behaving now if its not possessed even if a player controls it.

Best Regards,
Max

[Duwayne]

@twinflyer;514423

Controlling the Vehicle from the level Blueprint gives the desired result, but thats not a permanent solution.

I am running into the same issue where the vehicle seems to have cat like reflexes.

what did you change to make it not do it in the blueprints?

[xintoc]

You could use Enable Input, Add controls and motion and set the view target to that camera and disable the players movement and visibility. But it could be something you could fix by tweaking the movement component of the character.

[twinflyer]

I’m sorry, for some reason I was not notified up until now that this thread received replies.

The problem was on my side of things. I calculated some damping values and set the angular velocity of the pawn. In that calculation I forgot to take the current angular velocity into consideration resulting in resetting the angular velocity to a weird value. This lead to the behavior you see in the video posted above.

It worked all fine if the vehicle was controlled from the level blueprint because the pawn was not possessed and the false calculation I just mentioned was not called in this case.