Spritemanager 2 and Box Colliders

I am using SM2 to do a simple animation. I attached a packedsprite script on an empty game object which however i want to it to behave like a rigid body. The problem is that i have to change the dimensions of the box collider almost every time i run the game. Note that the dimensions of the collider do NOT change, but it seems that every time i run the game (almost every time) i have to use different collider dimensions for the object to collide properly.

Any ideas?

If your sprite is set to pixel-perfect, then its world size will change to remain pixel-perfect if your game view size changes. This means the collider you’ve added will no longer be the correct size. Pixel-perfect is really not what you want for in-game objects since relative sizes are critically important for in-game entities. Instead, pixel-perfect is good for things like UI. So turn pixel-perfect off and just size the object to the world size you want, and it will remain at that size.