Why does the object keep falling?

Questions & Answers
1

i have two objects, a drinking can and a bucket. can = rigidbody + box collider bucket = mesh collider

when the can goes into the bucket it's fine and it satys inside the bucket, but after you start moving the bucket the can starts falling down

how can i prevent this from happening?

QUESTION2: how can i enhance the framerate. i have 36 low poly (some small some big (size) ) models and when the player moves the fps goes down below 10. any help?

2

Mesh colliders must be convex to collide. This page has a table that lists the collision matrix

http://unity3d.com/support/documentation/Components/class-MeshCollider.html

There are many things which come into play when trying to optimize a game. In Unity you can go to Edit >> Project Settings >> Quality to tweak how it runs in the editor as well as the actual compiled game.

Here are some general tip from the Wiki on optimizing your game:

http://www.unifycommunity.com/wiki/index.php?title=General_Performance_Tips