You cannot expect equipment to reliably explode when destroyed by an explosion. At least, not all the time. It was quite a surprise when I threw an AP grenade to blast on impact on top of a vortex mine, and it didn't fire off.
The first thing I noted, volatile objects travelling in mid air that get caught in an explosion aren't affected at all. This means that it's okay to have an alien throw its shield high into the air and then have it drop all of its grenades to blast on impact or 0.25 seconds. The shield should be safe until it lands and not sustain any damage. I mean, if a Stun grenade can last a mid-air vortex mine explosion... But I suppose more tests might be useful.
The other, when on the ground, it is possible that the volatile object will get destroyed entirely without having any effect whatsoever (like they did in X-Com UFO). See, what I did was create a bread-crumb trail of AP grenades, then set it off at one end. I expected it to detonate all the way. The first AP grenade in the chain blew up (this being the secondary explosion), but it wiped out the second AP grenade without setting it off, ending the chain right there.
When I hit an explosive item with the very fringe of the AP blast, it didn't get destroyed. That's expected, since I don't think there was enough damage to breach through all the durability of the item. But on the next blast, it just vapourised it with no effect. On the other hand, without delivering any weak damage to the item beforehand, the item seemed to get set off quite regularly.
I wonder if too much damage is done that the item doesn't go off? I mean, if the damage puts its durability too far into the negatives, it just wipes it out, but if it's quite close +/- to 0 durability it goes off?
Hmm. Not too sure what to make of that, but I might just drop my use of the "extra super duper enhanced" proximity mine pile a bit - it might not be as potent as I thought. In any case, I can't rely on more than 1 fresh undamaged exposed item (of the same damage type). It's hard to tell if items are damaged or otherwise, since only armour parts show their durability.
Also, while experimenting with this, I noted something else. Dropping lots of explosives at blast on impact at the same time doesn't work so well when setting off an alien's entire stockpile of boomeroids at once. It's better to drop one on 0.25 or blast on impact, and set the rest to go off at 0.5 and 0.75 intervals but leave them in the backpack. This ensures at least 3 explosions in sucession. Being, 1 exposed (mid-air or contact with ground), 2 while it's in the backpack, and 3 whether it's still in the backpack or outside of it.
There might be more to it, but I think that should provide the best bang for your buck.
edit: On a less related note, the AP grenades have a much greater fringe than animated - I noticed this when my disrupter shields crackled when I was a tile or two away from the visible edge of the explosion. Most interesting indeed. Doesn't deal anything significant to armour, but can hurt unarmoured units.
Edited by NKF, 21 November 2007 - 02:17 AM.