With a blast weapon you may target a point of the battlefield (with an additional -2 penalty to hit after the 2023 rules update). So this is implied that you you can target a fighter 'normally' to avoid the -2 penalty to hit. However, what does targeting a fighter with a blast actually mean?
1. Do you place a blast marker's center anywhere above the target's base?
or
2. Do you place a blast marker's center above the target's base center? This could affect shooting models with large bases like brutes and ogryns
1. Do you place a blast marker's center anywhere above the target's base?
or
2. Do you place a blast marker's center above the target's base center? This could affect shooting models with large bases like brutes and ogryns