Does colision have anything to do with hitting/missing?

If a melee or missile opponent is engaged against a target with 0 collision will they have a hard time hitting them? Because my familiar has 0 collision and I noticed when an enemy was attacking him with Missile (splash) no AOE and a range of 150, he was missing the familiar everytime, but not with a "miss" notificaton, he was attacking but his attacks were just not inflicting any damage. but has no trouble hitting and hurting me.

Odd, i wasent aware of something like that. All i know collision of is 128grid spacing ratios (or something along those lines). As in "unit collision" were space is occupied depending on the collision, and another unit cannot be in that occupied area, so it has to move or get to the next closest spot.

Odd then why that would occur.

Possibly because WC3 does damage when AoE over laps with collision (seen by looking at AoE indicators). If there is no collision, how can they overlap?