I don’t know why but now when i import a mesh, then i add a rigidbody and a meshcollider ( with gravity ), then my mesh falls through my plane.
If i do the same operation with let’s say “create cube”, the cube stays fine on top of my plane.
Any idea what my mistake could be ?
It’s working fine on another of my project, but in this one, it doesn’t work anymore.
Patricia.
You cannot have mesh on mesh collisions. It is recommended to not use mesh colliders on rigidbody objects.
A plane isn’t a mesh though ? It may just be travelling too fast to detect the collision, try decreasing the timestep in the project settings. Also maybe a cube as the ground plane may improve the detection.
Ho ok, i added simple colliders around my objects, and it works now!
So what is the mesh collider use ? ( in what situations can it be used ? )
Thanks
patricia.
The default plane in Unity is a mesh and has by default a mesh collider attached.
A plane uses a mesh collider. What Forest was saying is that you have issues with mesh on mesh collisions.
You want primitive on mesh. That’s why using the default cube primitive works, it’s using a box collider.
You can add more than one collider to a mesh, so you can make a compound collider if you need to, or you can use raycasts depending on what you are doing.
[Edit: beat to the punch
]
HTH,
-Jeremy
It is good for static geometry. You can have primitive->mesh collisions, so you usually attach a mesh collider to the ground etc.
Note that for complex geometry, the mesh attached to the mesh collider is often a simplified version of the mesh attached to the renderer.
Edit
Damn Keli, type a bit slower will ya? 
-Jeremy
Thanks for your help, is there a way to edit the Box collider “visually” or do i need to type the values by hand in the “Box collider” section ?
Thank you
Patricia
Yeah by hand… or with a little trick
attach the collider to an empty game object that is on the hierarchy that your actual object and modify that with the handles
and attach scripts for the collider on that empty game object.
.ORG