Problems with gravity: jumping models

Questions & Answers
1

Hi all.

I’m pretty new to Unity and game development, so don’t judge me strictly.
I import a model of the rail track, add rigid body component (with mass 1 and use gravity flag) and box collider component. Then I add train engine with rigid body (mass == 1, user gravity) and box collider and put it on the track. When I’m running simulation, train engine starts jumping like a ball (despite material for tracks and train is Metal (built-in Unity material)).

There is an important note that rail tracks are fixed (freeze position set in rigid body options). It seems to be natural. Anyway, if I turn off freeze position option then train engine does not jump, but tracks fly apart.

So I’m in trouble here. Can you please suggest what is the problem?

Thanks in advance.

2

I’m thinking the TRACKS should NOT HAVE a rigidbody … in fact you just want a COLLIDER on the tracks.

TRACKS == collider, NO rigidbody

TRAIN CARS == collider + rigidbody + gravity

Does it help?

Regarding freezing (this is on the Cars). Turn it all off (unchecked) at first. Possibly you want to freeze the Z value, but don’t worry about it at first, it should work anyway.