Hi guys, pretty new to unreal but enjoying it so far.
I’m currently building a simple hover vehicle, using line traces/lerps for my hover components and a physics thruster for forward/backwards movement.
The problem is with my forwards/backwards movement… I’ve set the Thrust Force, however my vehicle is experiencing a maximum velocity. As in, it accelerates to about 316 units/s (which is far too slow), after which it stops accelerating and keeps going at about the same speed.
If the physics thruster acts as a force (which I believe it does, since the parameter is named Thrust Force), then assuming 0 air resistance the vehicle should accelerate indefinitely… right?
I’ve tried playing around with the “linear damping” parameter in my body but it doesn’t seem to have an effect at all unless I make it negative (in which case my vehicle disappears into the sunset, never to be seen again).
Additionally, once I stop applying a force, the vehicle should continue moving at its current velocity, but it stops almost immediately.
My assumptions are therefore either:
a) I’ve misunderstood how physics thrusters work (or my physics is just completely off…); or
b) There’s a hidden value for air resistance somewhere.
This is doing my head in! Anyone got any input on this topic?
Check to make sure linear and rotational dampening are set to 0 (just for testing, not permanently or it’ll never stop), that might be slowing it down. The engine doesn’t even have air resistance (aside from dampening faking it), so it’s probably either that or something else you have exerting force on the object (like friction against another mesh or a thruster in the other direction).
And as you saw, it’s not the max velocity, since your vehicle went well and far off into the distance when you did negative dampening. So it -can- go faster than what you have it at right now.
I would just do standard debugging. Turn off -everything- acting force onto the object, then put in an absurd number like 100000000 into the thruster and see what happens. If it works at the full speed, you now narrowed down your problem to something you disabled.
Thanks for the reply. Unfortunately none of that seems to work?
Here’s a picture of my physics settings, and I’m still getting a max speed of around 310.
Interestingly making the linear damping negative doesn’t actually make a difference to the horizontal velocity of the car, as I first thought, it just makes it fly directly upwards (there are forces operating from the bottom to counteract gravity).
I’ve tried removing all other forces but it doesn’t make a difference. Is there an option in the editor to see all forces acting on an option (as arrows maybe)? I looked around but couldn’t find anything.
Thanks again for your response!
EDIT: Just noticed in my picture that the tooltip is covering some of it up. The value for angular damping is 0.0 and gravity is enabled.
Can you post a google drive project link? I could figure it out for you pretty quick. The maximum threshold is somewhere around 140,000 m/s before there starts to be graphical glitches and collision stops working so you’ll get it. I prefer to use an acceleration vector over physics thrusters because the physics are tied to the framerate so you’ll get velocity relative to framerate which is not ideal as you’ll speed up and down as the framerate changes.
Okay so after racking my brains I finally worked it out. I’ll write out the problems and how I fixed it here, in case anyone else has the same problem as me.
The problem was in my “hover components” (not sure how I didn’t discover that when I was removing all components, but we’ll put that down to me being an idiot).
So if you follow any of the tutorials I found for creating a hover vehicle, such as this official Unreal one, or this unofficial but very well put together one, you may notice at the end they both include a linear damping. This value overrides any value you set on the body, which explains why I didn’t notice a change. I figure I only noticed a change once i put it really high because the initial damping made it fly around.
However, if you take away this damping you get a very unstable hovering, and no one wants that.
So what I did was add in a P controller (proportional), that just changes the force based on velocity. See below. Hopefully that helps.
