2 boxcolliders don't collide

Unity Engine
1

Ok Guys, sorry to bother you with this “easy” quesetion but this is my problem:

I have an object .OBJ I load from a file and I assign a BoxCollider as the MeshCollider is limited to 255 triangles. Anyway… my floor plane has also a box collider… so, I place my objects above the floor so I’m expecting them to fall. And they fall, but they keep falling as no boxCollider is attached… how is that possible? I’m sure the objects are well above the floor. Are 2 box Colliders supposed to hit each other?

Merci.
Giancarlo

2

Yes, they should collide.
obvious question: Both of them are not marked as trigger , rigth?

3

Well, it does not require a rocket scientist to figure that out. Things will not fall without gravity. :smile: Lols…

On a serious note, you want to check what kind of components your game object has. To do that, you can do the following:

  1. Run your game in the Unity
  2. Select Layout (2 by 3)
  3. Select your game object in the Hierarchy
  4. Check the Inspector. That is the answer to your question.
4

Uhm… thanks guys for the help, still trying to figure out what’s the problem. (All the boxColliders I have are IsTrigger = false)
I have a plane set in the Unity editor… this plane has a BoxCollider.
But the objects I load are .OBJ files I parse with a Parser I made. As soon as the mesh is built up, I add a BoxCollider which I think, needs to be as big as the bounds of the mesh. So Before adding a boxCollider I call mesh.RecalculateBounds() in order to compute the new bounds and then I add the BoxCollider Component to the gameobject.
The gravity makes them falling through the plane and they don’t stop :((

5

do not know if that can be your issue but to have any kind of collision one of your object ( probably best the plane in that case ) may have a rigidbody to it.
adding only collider won’t get you any kind of triggering or collsion without at least on of the object interacting havong a rigidbody component to it

6

Well my objects have a RigidBody as they fall down because of the gravity (I guess). My suspect is that the BoxCollider attached to the uploaded objects is not “big” enough to collide with the BoxCollider of the floor in my scene…and still I don’t quite get how to set the dimensions of those boxColliders.
I have also objects to which I attach a MeshCollider (convex) (Plus a rigidBody) and they interact really well.

Dunnow… seems a bit weird behaviour and I am making a 3D environmnet for the web so this is slightly more annoying as the debugging is not that easy.

7

Yes that’s what I suspected:

adding these two lines it made everything work…

ms[0].GetComponent().mesh.RecalculateBounds();
ms[0].AddComponent(typeof(BoxCollider));