>>535708209
>Basically, explosions only deal any damage on a tiny itty bitty microscopic dot on the very center. Then, deal like no damage after that. Rather than being a decay or something more logical.
But explosive damage does 'decay' over distance. If explosions only ever did their damage in a tiny microscopic dot in the center of the effect weapons like the grenade launcher or any of the explosive grenades just wouldn't function, yet you can clearly see grenades blowing up entire packs of chaff.
Every explosion has an inner radius and an outer radius. Within the inner radius the explosion does 100% of its listed damage value, and then over the distance from the inner radius to the outer radius the damage gradually falls off to 0. I've made this webm so you can see this in action very easily. With the exploding crossbow, which has a 3 meter inner radius and a 6 meter outer radius, you take significantly less damage shooting it into the ground a few meters away from you than you do shooting it directly at your feet. That's the explosive damage decaying over distance, not instantly dropping off into nothing. Some weapons like the punisher plasma and the purifier have an near identical inner and outer radius but that's not common.

As for what parts of an entity an explosion deals damage to it depends entirely on what parts of that entities various hitzones are inside of the explosion radius, and to which degree those parts have explosive damage reduction. yes, some entities like bot raiders have a 'main' hitzone that isn't a visible part of their body that might be a very small physical hitbox buried in the model somewhere, but there are plenty of enemies whose main bodies or torsos are their main hp hitzone. scavs, warriors, and hulks all come to mind immediately as enemies that have completely tangible main hitzones. The hulks entire body other than its limbs, eye, and heatsink is its main HP hitzone.