Picking Up Objects Within Range

I’m in the process of making a very interesting and experimental sandbox, RTS, puzzle, and adventure game all in one, and I’m trying to get one of the key components to work, which is picking up objects. I have tried using raycasts with the mouse, but seeing as it’s a 3rd-person game, it doesn’t quite function how I’d like it to. What I want to accomplish is as you get close enough to any object able to be picked up (assuming tags here) and when the user presses a key, the object gets carried/dragged along with the character until the key is pressed again. All the key presses and such aren’t a problem for me, it’s just the actual attaching of the object to the character, and doing it within a certain distance.

Thanks so much!

I think a very simple idea for someone who is still learning, would be that you should use collision detection and on enter of an objects collision(boundry box or invisible collider object) and on all objects within collision are entered it picks them up, and the range can be set by the size of the object thats detecting the collision, as so.

http://forum.unity3d.com/threads/33091-SOLVED-Collision-detection-without-physics

possibly a invisible plane/sphere with a size and collision detection without physics should do ok.