Car Physic Issue

Hi there!

Short Stories: Our NPC Vehicles are flying and bouncing.

We’re experiencing a weird physic issue with our NPC Vehicles. We’ve added some Vehicles from an older project, which were created in 3DS Max 2013 with Meters as Unit System. They were exported as FBX using the Automatic Unit Settings. So, they’re being converted into Centimeters. Physic is behaving correctly with those Vehicles.
Unfortunately, if we add Sockets to the Vehicle the Socket doesn’t behaves correctly. It’s 100x larger and rotates 100x slower.

So, we setup up some of our vehicles again, but this time in Centimeters before Export. Rigged them all a new and so on. Sockets appear correct on those Centimeter-Vehicles. But the Physic is just going crazy. The Vehicles are flying and bouncing through the scene.

We’re using UE4.10.3

Any help on this?

  1. Realistic car physics can be improved in UE4. It might be a sideeffect of it.
  2. Make the base as a pawn or character, its way less headaches or look @BoredEngineer 's thread, it has alternatives for working with physics.

Thanks. We’re currently fixing it.

Before going all the way with custom physics vehicle implementation I would still consider vehicle template unless you want some features which are not there or some issues with it are really critical to gameplay.
Physics going crazy is usually indication that some collision meshes overlap. Check that your wheels are not intersecting chassis or disable collision between them and chassis in the phat editor on the level of constraints. Mass can play big role in this too. Usually PhysX vehicles are twice as heavy as their real-life models. This adds to stability.
Another thing to consider is proper pivots for the root body and wheels orientation.
Post screenshots of your setup, we might spot if something is set weird.

We’re using standard vehicle physics for our npc vehicles. Our custom physic is for our player vehicle only, as it is quiet complex.

Seems to have been a compiling bug with the npc vehicle physic. We’ve unticked some features, compiled, ticked them again, compiled again, and now it works fine.