I don't follow you.
CampFire/Forge AOE mechanic - Don't think we can use this for Radiation. We could then end up with a radiation effect from every block near you which would be a huge performance hit I'd guess if done as Campfire/Forge effect. Though if you reversed it, and had the effect kind of work backwards originating at the player to determine if an effect would be triggered, maybe?
Not sure how block distribution works in this.
Layer Depth Placements is a part of the world generation process, a hugely non-performant task. Which is why it's in world gen processes.
On impact properties. What if I just don't move. I don't get a radiation effect?
Buffs? I think the best tie in here is the walk across effect you can apply to asphalt and such. From an activation perspective. Explosions? If we're talking about something like shale exploding, that'd be simpler, like tweaking the drop/turns into functionality I'd imagine or block damage received process.
Sorry, I think you're commenting on a lot of points in several smaller bullet points. <3 I'm lost homie.
They can make a buff the reacts just like radiation. Buffs are easy to make and use.
The AOE mechanic of the campfire/forge already uses and applies a type buff's. <property name="ActiveRadiusEffects" value="+heatSource(3)"/>
We (as a modder) don't get to play with the AOE mechanic but none the less the heatSource(3) is a type of buff.
Blocks can already have a property that acts when you hit it (ie using a pick on a gas barrel). Which is what you would need since the player is generally digging out all around them and would be more effective then the "walksOnBuff"
Specific Blocks can already be placed in just about any layer you want or can be distributed like ore. To be distributed evenly starting at whatever level/layer you want. If the block is inert (not triggered) its just another block. Little to know cost.
Don't really a chain of blocks to activate to apply a AOE buff to the player. You just need that specific block to apply the area of effect once activated. which the area of effect could be set at 60 or higher and then deplete on a timer. A one fire activation to apply a buff on the player in the area. Which makes the player take either move away from area to debuff or apply an item to debuff (gas mask of something).
If you are digging and destroying blocks to dig out your lair you would "crack open a gas pocket" at some point.
I disagreed with your premise on how to get underground radiation or whatever gas to work. I could be wrong but I don't think it needs to be overly complicated like you're describing. Nor does the voxel map need to be fixed for that reason maybe for other reasons but not the one your describing.
Edit: oh yeah. Quest notes when digging for treasure is something as well.
I just think Kinyajuu's and Primes idea can be applied in many ways besides the zed.