[Colliders?] Popping out from a terrain

Unity Engine
1

Hello,
I’d want to have something like “Effector2D” but on a 3D scene. I have an object under my Terrain and with an “AddForce” I would like this object to be fired out of the ground and then fall back on the ground (terrain). So I’d need a kind of “One way” collision with this object and the ground …

what would you suggest me to do?

Thanks!

2

You could just instantiate the object just above ground and apply force, or is it necessary to see it actually moving through the ground?

3

Do you expect the object to collide with anything else during its flight path? How predictable is the flight path? Is it always going to have at least a certain amount of hang time?

One option is make its collider start as a trigger collider, then when you detect OnTriggerExit with the ground, you can convert the trigger collider into a non-trigger collider.

Another option is disable the collider until the vertical velocity becomes negative (could be problematic if your terrain has overhangs or if you expect the object to collide with other things.

Another option is Physics.IgnoreCollision specifically with the ground until some criteria is met (negative y velocity, some amount of time passed, trigger exit with some smaller ground trigger you place around the object itself.

There’s a lot of options here. I think you’ll have to use at least one of the following in some way:

  • Physics.IgnoreCollision
  • Layer-Based collision (either changing layers of the objects at some point or using Physics.ignoreCollision with certain layers at certain points)
  • Disabling/enabling/creating a collider at some point
  • Changing a collider from trigger to non-trigger at some point.