Having Trouble Retuning an Object to be Passed Through

Hi there. I've been trying my hand at retuning items, namely the hollow log debug item. I was able to make it buyable, but my real goal is to retune it so that a sim can walk through it. I know that usually impassable objects can be retuned into passable objects, because I've seen CC on Mod the Sims of tall grass and rocks that have been modded this way. So, my question is, what tags should I use to get the desired result? Please help, because I'm really stumped (no pun intended) on this one.